Inclusion Criteria:

        Participants must meet all of the following inclusion criteria to be eligible to enroll in
        the Part C of this study.

          1. Should have unresectable advanced, recurrent or metastatic melanoma and must have
             objective and measurable melanoma by RECIST 1.1 after disease progression on a prior
             anti-PD-1 or anti-PD-L1 therapy.

          2. ECOG performance status of ≤ 2.

          3. Life expectancy of ≥ 3 months.

          4. Adequate hepatic function:

               -  Total bilirubin < 1.5 times the ULN (except participants with Gilbert's syndrome
                  [hereditary indirect hyperbilirubinemia] who must have a total bilirubin of ≤ 3
                  times ULN),

               -  AST and ALT ≤ 2.5 times ULN (except participants with known liver involvement of
                  their advanced solid malignancy who must have an AST and ALT ≤ 5.0 times ULN).

          5. Adequate renal function:

               -  Estimated creatinine clearance of ≥ 60 mL/min, calculated using the formula of
                  Cockroft and Gault (140-Age) Mass (kg)/(72 creatinine mg/dL); multiply by 0.85 if
                  female.

          6. Adequate hematopoietic function:

               -  Total WBC count ≥ 1500/mm³, ANC ≥ 1000/mm³, Hb ≥ 10.0 g/dL, platelet count ≥
                  100,000/mm³

        Exclusion Criteria:

        Participants meeting any of the following exclusion criteria are not eligible to enroll in
        this study.

          1. ≤ 2 weeks since the last prior therapeutic regimen for melanoma. Palliative steroids
             for disease related symptoms < 7 days prior to C1D1, unless physiologic doses of
             steroids are used.

          2. Have not recovered or stabilized (Gr 1 or to their baseline for non-hematologic
             toxicities, ≤ Gr 2 or to their baseline for hematologic toxicities) from toxicities
             related to their previous treatment except for alopecia.

          3. Untreated CNS disease or leptomeningeal involvement are excluded. Participants without
             active brain or leptomeningeal metastases after prior treatment with local therapies
             are eligible provided that the treatment had been done ≥ 2 weeks prior to enrollment.

          4. Active infection with completion of therapeutic antibiotics, antivirals, or
             antifungals within one week prior to C1D1. Prophylactic antibiotics, antivirals or
             antifungals are permitted.

          5. Significantly diseased or obstructed gastrointestinal tract or uncontrolled vomiting
             or diarrhea that could interfere with the absorption of KPT-9274.

          6. Active peptic ulcer disease or other active gastrointestinal bleeds.

          7. Requiring treatment with corticosteroids at doses higher than substitute therapy (> 10
             mg prednisone), are unstable with substitute hormonal therapy, or are deemed to be
             likely to re-occur by the treating physician when administered nivolumab.