5. Prior therapy for melanoma with the following exceptions which are allowed: 1) surgery for the melanoma lesion(s), 2) adjuvant RT after neurosurgical resection for CNS lesions, and 3) prior adjuvant IFN (see qualifier below). Specifically, patients who received prior therapy with anti-PD-1, anti PD L1, anti-PD-L2, anti-CD137, or anti-CTLA-4 antibody (including ipilimumab or any other antibody or drug specifically targeting T cell costimulation or checkpoint pathways) are not eligible.