The development of effective adjuvant therapies for patients with high-risk melanoma has included ipilimumab (an anti-CTLA-4 antibody), pembrolizumab and nivolumab (both monoclonal antibodies against programmed death 1 [PD-1]), and combination of BRAF and MEK inhibitors for patients whose tumors harbor a BRAF mutation1,4–12, leading to US Food and Drug Administration approvals. Here, CTLA4 is linked to melanoma.