An Italian study evaluated the effects of five PD-1 SNPs (PD1.3 G>A, PD1.5 C>T, PD1.6 G>A, PD1.7 T>C, and PD1.10 C>G) and three PD-L1 SNPs (+8293 C>A, PD-L1 C>T, and PD-L1 G>C) in metastatic melanoma patients treated with nivolumab or pembrolizumab. Here, PDCD1 is linked to metastatic melanoma.