Immune checkpoint inhibitors (ICIs) have resulted in favorable outcomes in patients with melanoma both in the metastatic and adjuvant settings, and the use of neutralizing antibodies targeting programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) are now clinically approved in many countries [2]. Here, PDCD1 is linked to melanoma.