High Dose IL-2 in Combination With Anti-PD-1

PrimaryObjective Determine the overall response rate (complete response and partial response) for patients receiving anti-PD-1 (nivolumab) and high dose IL-2 (HD IL-2) in subjects with metastatic melanoma or renal cell carcinoma who have previously progressed on anti-PD-1 therapy. Response assessment will be performed using revised RECIST guideline (v 1.1). Secondary Objectives * Characterize safety, tolerability and adverse effects (AE) profile of nivolumab with HD IL-2 in subjects with metastatic malignant melanoma or renal cell carcinoma * Measure Progression-Free Survival (PFS) using RECIST 1.1 after completion of at least one course of therapy (2 doses of nivolumab, 2 cycles of HD IL-2) for subjects enrolled in the study. ExploratoryObjectives * Correlate PD-L1 expression and tumor mutational burden (TMB) in archived diagnostic tumor tissue with best clinical response for subjects with metastatic melanoma and renal cell carcinoma * Correlate myeloid-derived suppressor cells and T-cell subsets in peripheral blood during therapy with best clinical response (RECIST criteria) and treatment outcome in subjects with metastatic melanoma or renal cell carcinoma. Data will be collected prior to each treatment and after each course of treatment. Study Duration: 48 months Amount of Subjects: up to 25 subjects