A phase I clinical trial of Nivolumab (BMS-936559 IgG4 antibody to PD-1) in combination with Ipilimumab (IgG1 antibody to CTLA4) in 86 patients with stage III or IV melanoma (53 received concurrent therapy and 33 received sequential therapy) showed a 53% objective response rate at 2.5-year follow-up; in the concurrent treatment group there were marked tumor reductions of over 80% compared to 20% objective response rate (ORR) for sequenced treatments. This evidence concerns the gene CTLA4 and melanoma.