Inclusion Criteria:

        Patients must meet all of the following inclusion criteria to be eligible for participation
        in the study:

          1. Histopathologically confirmed diagnosis of advanced, unresectable or metastatic
             malignant melanoma

          2. Male or female patients age 18 or older

          3. Previously treated with checkpoint inhibitor therapy either alone or in combination
             with either stable disease or progressive disease per RECIST version 1.1 (there is no
             minimum treatment duration for patients who have progressive disease while on
             checkpoint inhibitor therapy)

          4. Measurable or evaluable disease by RECIST version 1.1

          5. Capable of understanding and complying with protocol requirements

          6. A life expectancy of greater than 24 weeks at Screening

          7. ECOG Performance Status of 0 to 2

          8. Written informed consent from the patient or the patient's legally acceptable
             representative prior to the initiation of any study procedures

          9. Adequate bone marrow, liver, and renal function as defined below:

               -  hemoglobin ≥8.0 g/dL (transfusions allowed)

               -  absolute neutrophil count ≥1500/µL

               -  platelet count ≥100,000/µL (transfusions allowed)

               -  alanine transaminase and aspartate transaminase ≤3.0 times the upper limit of
                  normal (ULN), or ≤5 times ULN for patients with known hepatic metastases

               -  total serum bilirubin ≤1.5 x the ULN; ≤2.0 x the ULN if liver metastases are
                  present; patients with a known history of Gilbert's syndrome (≤3.0 x the ULN)
                  and/or isolated elevations of indirect bilirubin are eligible for study
                  participation

               -  estimated glomerular filtration rate ≥50 mL/min/1.73 m^2 (using Cockcroft Gault
                  formula)

        Exclusion Criteria:

        Patients who meet any of the following criteria will not be eligible for participation in
        the study:

          1. Pregnant or breast feeding

          2. Developed immune-related toxicity while on prior checkpoint inhibitor therapy that has
             not yet returned to Grade 1 or better

          3. Require systemic pharmacologic doses of corticosteroids at or above the equivalent of
             10 mg/day of prednisone; replacement doses, topical, ophthalmologic and inhalational
             steroids are permitted

          4. Active, symptomatic central nervous system (CNS) metastases. Patients with CNS
             metastases are eligible for the trial if the metastases have been treated by surgery
             and/or radiotherapy and the patient is off corticosteroids and is neurologically
             stable for at least 7 days prior to screening

          5. Any concurrent uncontrolled illness, including mental illness or substance abuse which
             in the opinion of the investigator would make the patient unable to cooperate or
             participate in the trial

          6. Severe uncontrolled cardiac disease within 3 months of study entry, including unstable
             or new onset angina, myocardial infarction or cerebrovascular accident

          7. Women of childbearing potential who are unable or unwilling to use an acceptable
             method of contraception

          8. Known infection with human immunodeficiency virus (HIV) that is not well controlled on
             anti-retroviral therapy as defined by HIV RNA more than 400 copies/mL or severely
             symptomatic

          9. Presence of Hepatitis B and/or Hepatitis C active infection

         10. Symptomatic congestive heart failure, defined as New York Heart Association Class II
             or higher