Antibodies blocking the interaction between PD-1 and PD-L1 by either targeting PD-1 (pembrolizumab, nivolumab, and cemiplimab) or PD-L1 (atezolizumab, avelumab, and durvalumab) (Table 1) both induce durable objective responses in patients with melanoma (1, 2), NSCLC (3–5) and RCC (6), and other malignancies (7–15). This evidence concerns the gene PDCD1 and melanoma.