Nivolumab, an anti-PD-1 mAb, and ipilimumab, an anti–CTL-associated antigen 4 (CTLA-4) mAb, are immune checkpoint inhibitors that have shown antitumor activity in several malignancies, including melanoma, renal cell cancer, lung cancer, and hepatocellular cancer (11–14). Here, CTLA4 is linked to melanoma.