Eligibility Details:  
        Inclusion Criteria:
          1. Age ≥ 18 years
          2. Written informed consent must be obtained from all patients prior to any study
             procedures
          3. Patients with advanced non-uveal melanoma defined as unresectable stage III or
             metastatic stage IV disease. Patients with acral or mucosal melanoma are acceptable.
             Patients with melanoma of unknown primary are acceptable for Phase Ib cohorts (Arms 1
             to 4), but are excluded in Phase II cohorts. Patients with the diagnosis of UM are
             excluded from all cohorts.
          4. Phase 1b Arm 4 and Phase II: Patients with disease progression following initiation of
             treatment with an approved PD-1 inhibitor. No prior cytotoxic therapy in the advanced
             setting is permitted. Patients with BRAF mutations must be refractory to approved
             BRAF-based therapy. CTLA-4-inhibition therapy is acceptable as a prior line of therapy
             or in combination with anti-PD-1 therapy.
          5. No longer applicable - (Phase II IMT naive cohorts: Patients have not received
             systemic cytotoxic or immune-based therapy for advanced melanoma. BRAF and/or MEK
             inhibition therapy is acceptable before immunotherapy where clinically indicated.
             Other systemic cytotoxic or targeted therapy in the advanced setting is not permitted
             in this subset)
          6. Phase Ib Arms 1, 2, and 3: no restriction on prior therapy
          7. HLA-A*0201 positive by Central Assay
          8. Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1
          9. Life expectancy of at least 3 months
         10. Phase II cohorts only: patients must have measurable disease according to RECIST v.1.1
             criteria. Patients enrolled in Ph Ib cohorts must have evaluable disease
         11. Phase 1b Arm 4 and Phase II cohorts only: Patients must have a site of disease
             amenable to biopsy, that is not an index lesion, and be a candidate for tumor biopsy
             according to the treating institution's guidelines. Phase Ib Arms 1-3 patients need
             not have disease accessible to biopsy
         12. Those receiving prior immunotherapy must meet all of the following conditions:
               -  Must not have experienced an immune-related adverse event (irAE) where the irAE
                  was the reason for permanent discontinuation of prior immunotherapy in the most
                  recent prior treatment regimen
               -  All irAEs while receiving prior immunotherapy must have resolved to ≤ grade 1 or
                  Baseline prior to Screening for this study. Must not have experienced a ≥ grade 3
                  immune-related AE within the past 16 weeks or any grade 4 life- threatening irAE
                  (regardless of duration) or neurologic or ocular AE of any grade while receiving
                  prior immunotherapy (NOTE: Subjects with endocrine AE of any grade are permitted
                  to enroll if they are stably maintained on appropriate replacement therapy, but
                  must have no history of adrenal crisis and be asymptomatic)
               -  Patients currently receiving chronic corticosteroid treatment (longer than 8
                  weeks duration) for management of pre-existing adverse events, or patients with a
                  history of chronic corticosteroid treatment longer than 8 weeks' duration for AEs
                  within 6 months of Screening are excluded
        Exclusion Criteria:
          1. Presence of untreated or symptomatic central nervous system metastases, or central
             nervous system metastases that currently require local therapy (such as radiotherapy
             or surgery), or require doses of corticosteroids within the prior 4 weeks
          2. History of severe hypersensitivity reactions to other mAbs
          3. History of treatment-related interstitial lung disease/pneumonitis
          4. Patient with any out-of-range laboratory values defined as:
               -  Serum creatinine ≥ 1.5 x ULN and/or creatinine clearance (calculated using
                  Cockcroft-Gault formula, or measured) < 50 mL/min
               -  Total bilirubin > 1.5 x ULN, except for patients with Gilbert's syndrome who are
                  excluded if total bilirubin > 3.0 x ULN or direct bilirubin > 1.5 x ULN
               -  Alanine aminotransferase (ALT) > 3 x ULN
               -  Aspartate aminotransferase (AST) > 3 x ULN
               -  Absolute neutrophil count (ANC) < 1.0 x 10^9/L
               -  Absolute lymphocyte count < 0.5 x 10^9/L
               -  Platelet count < 75 x 10^9/L
               -  Hemoglobin (Hgb) < 8 g/dL
               -  Potassium, magnesium, corrected calcium or phosphate abnormality of National
                  Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) >
                  grade 1
          5. Clinically significant cardiac disease or impaired cardiac function, including any of
             the following:
               -  Clinically significant and/or uncontrolled heart disease such as congestive heart
                  failure (New York Heart Association [NYHA] grade ≥ 2), uncontrolled hypertension
                  or clinically significant arrhythmia currently requiring medical treatment
               -  QTcF >470 msec on screening ECG or congenital long QT syndrome
               -  Acute myocardial infarction or unstable angina pectoris < 6 months prior to
                  Screening
          6. Active autoimmune disease or a documented history of autoimmune disease within 3 years
             before Screening (or as indicated below), including the following:
               -  A documented history of inflammatory bowel disease (ulcerative colitis or Crohn's
                  disease, within three years)
               -  Patients with vitiligo, alopecia, managed hypothyroidism (on stable replacement
                  doses), psoriasis, resolved childhood asthma/atopy, well-controlled asthma and
                  type I diabetes mellitus are NOT excluded
          7. Recent (< 12 months) active diverticulitis (PhIb combination arms and PhII only)
          8. Active infection requiring systemic antibiotic therapy. Patients requiring systemic
             antibiotics for infection must have completed therapy before Screening is initiated
          9. Known history of human immunodeficiency virus (HIV) infection. Testing for HIV status
             is not necessary unless clinically indicated or if required by local regulation
         10. Active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection, currently
             requiring medical intervention, per institutional protocol. Testing for HBV or HCV
             status is not necessary unless clinically indicated or the patient has a history of
             HBV or HCV infection requiring treatment with currently an unknown status. History of
             treated hepatitis is not exclusionary
         11. Malignant disease, other than that being treated in this study. Exceptions to this
             exclusion include the following: malignancies that were treated curatively and have
             not recurred within 2 years after completion of treatment; completely resected basal
             cell and squamous cell skin cancers; any malignancy considered to be indolent and that
             has never required therapy; and completely resected carcinoma in situ of any type
         12. Any medical condition that would, in the investigator's judgment, prevent the
             patient's participation in the clinical study due to safety concerns, compliance with
             clinical study procedures or interpretation of study results
         13. Systemic anti-cancer therapy within 2 weeks of the first dose of study treatment. For
             cytotoxic agents that have major delayed toxicity and any prior immunotherapy
             approach, 4 weeks is indicated as washout period
         14. Presence of National Cancer Institute Common Terminology Criteria for Adverse Events
             (NCI CTCAE) ≥ grade 2 toxicity (except alopecia, peripheral neuropathy and
             ototoxicity, which are excluded if ≥ NCI CTCAE grade 3) due to prior cancer therapy
         15. Patients currently requiring chronic, systemic corticosteroid therapy at any dose for
             longer than 2 weeks. Local steroid therapies (eg, otic, ophthalmic, intra-articular or
             inhaled medications) are acceptable
         16. Use of any live vaccines against infectious diseases within 4 weeks of initiation of
             study treatment. Non-live vaccination (eg, influenza) are permitted anytime during
             treatment
         17. Major surgery as defined by the investigator within 2 weeks of the first dose of study
             treatment (minimally invasive procedures such as bronchoscopy, tumor biopsy, insertion
             of a central venous access device, and insertion of a feeding tube are not considered
             major surgery)
         18. Radiotherapy within 2 weeks of the first dose of study drug, with the exception of
             palliative radiotherapy to a limited field, such as for the treatment of bone pain or
             a focally painful tumor mass
         19. Use of hematopoietic colony-stimulating growth factors (eg, G-CSF, GMCSF, M-CSF) ≤ 2
             weeks prior start or study drug. Patients must have completed therapy at least 2 weeks
             before the screening period begins with any hematopoietic colony-stimulating growth
             factors. An erythroid stimulating agent is allowed as long as it was initiated at
             least 2 weeks prior to the first dose of study treatment and the patient is not red
             blood cell transfusion dependent
         20. Pregnant or lactating women, where pregnancy is defined as the state of a female after
             conception and until the termination of gestation, confirmed by a positive hCG
             laboratory test
         21. Women of child-bearing potential who are sexually active with a non-sterilized male
             partner, defined as all women physiologically capable of becoming pregnant, unless
             they are using highly effective contraception from screening throughout study
             treatment, and must agree to continue using such precautions for 6 months after the
             final dose of investigational product; cessation of birth control after this point
             should be discussed with a responsible physician. Highly effective methods include the
             following:
               -  Total abstinence from sexual relations for the duration of the treatment when
                  applicable to the lifestyle of the patient. Periodic abstinence (eg, calendar,
                  ovulation, symptothermal, post-ovulation methods) and withdrawal are not
                  acceptable methods of contraception
               -  Female sterilization (have had surgical bilateral oophorectomy with or without
                  hysterectomy) or tubal ligation at least 6 weeks before taking study treatment.
                  In case of oophorectomy alone, this applies only when the reproductive status of
                  the woman has been confirmed by follow up hormone level assessment
               -  Male sterilization (at least 6 months prior to Screening). For female patients on
                  the study the vasectomized male partner should be the sole partner for that
                  patient
               -  The combination of any 2 of the following methods when both are used
                  simultaneously:
                    1. Use of oral, injected, or implanted hormonal methods of contraception or
                       other forms of hormonal contraception that have comparable efficacy (failure
                       rate <1%), for example hormone vaginal ring or transdermal hormone
                       contraception
                    2. Placement of an intrauterine device or intrauterine system
                    3. Barrier methods of contraception: condom or occlusive cap (diaphragm or
                       cervical/vault caps) when used with spermicidal foam, gel, film, cream, or
                       used of a spermicidal vaginal suppository Women of child-bearing potential
                       must have a negative serum pregnancy test at Screening. Otherwise, female
                       patients must be post-menopausal (no menstrual period for at least 12 months
                       prior to Screening), or surgically sterile.
         22. Male patients must be surgically sterile or use double barrier contraception method
             from enrollment through treatment and for 6 months following administration of the
             last dose of study drug.