 Tumor assessments will be done every 3 months. All patients with objective tumor response must have additional scans scheduled 4-6 weeks after the criteria for response are first met in order to confirm the response. Additional scans will be done if clinically indicated. Survival will be monitored on all patients for up to 5 years from the date of first dose of CP-675,206. The follow up time may be adjusted based on ongoing studies using CP-675,206 for melanoma. 