Inhibition of the PD-1/PD-L1 interaction with therapeutic antibodies, such as pembrolizumab, nivolumab, or atezolizumab has emerged as an effective treatment for several cancers, including melanoma (3, –5), renal clear cell carcinoma (6), nonsmall cell lung cancer (7, –9), urothelial carcinoma (10, 11), and head and neck carcinoma (12). This evidence concerns the gene PDCD1 and melanoma.