Pfizer PF-06688992 in Patients With Stage III or Stage IV Melanoma

Inclusion Criteria: * Histological diagnosis of melanoma confirmed at MSKCC * Measurable unresectable Stage III or IV Malignant Melanoma and Response Criteria in Solid Tumors \[RECIST\], Version 1.1. * Patients must have progressed on prior approved checkpoint inhibitor therapy, not tolerated approved checkpoint inhibitor therapy, or have a contraindication to approved checkpoint inhibitors. Patients with stable disease after approved checkpoint inhibitor therapy will also be eligible. * Patients whose melanomas harbor a BRAF V600E or V600K mutation must have progressed on a RAF inhibitor. Patients who had to discontinue RAF inhibitor therapy because of toxicity but who did not progress will be eligible unless they responded to therapy. In that case, they will not be eligible unless they progress. * Age ≥ 18 years * ECOG performance status 0-1. * Adequate Bone Marrow Function as defined by: °≥1,500/mm\^3 or ≥ 1.5 x 10\^9/L; * Platelets ≥ 100,000/mm3 or ≥ 100 x 109/L; * Hemoglobin ≥ 9 g/dL. * Adequate Renal Function as defined by: * Serum creatinine ≤ 1.5 x upper limit of normal (ULN); or * Estimated creatinine clearance ≥ 60 mL/min as calculated using the method standard for the institution. * Adequate Liver Function as defined by: * Total serum bilirubin ≤ 1.5 x ULN unless the patient has documented Gilbert syndrome; * Aspartate and Alanine Aminotransferase (AST \& ALT) ≤ 2.5 x ULN; ≤ 5.0 x ULN if there is liver involvement secondary to tumor; * Alkaline …