Long et al., have investigated 355 patients in a multicenter, retrospective, cohort study with metastatic melanoma resistant to anti-PD-(L)1 (nivolumab, pembrolizumab or atezolizumab) that received either ipilimumab monotherapy or ipilimumab plus anti-PD-1 therapy [2]. This evidence concerns the gene PDCD1 and metastatic melanoma.