This is a Phase 3, multi-national, open-label, 2-arm randomized study in patients with surgically incurable metastatic melanoma who have received no prior chemotherapy, or biochemotherapy for the treatment of metastatic disease. The primary objective of this trial is to compare overall survival for patients with advanced melanoma who are randomized to receive CP-675,206 with that of patients who are randomized to receive either dacarbazine or temozolomide (investigator choice)