Trials with the cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) inhibitor ipilimumab and the programmed cell death protein 1 (PD-1) inhibitors nivolumab and pembrolizumab have shown profound improvements of survival in patients with unresectable or metastatic melanoma.7–9 In a pooled analyses of clinical trials, mucosal melanomas, however, had lower response rates to nivolumab and pembrolizumab compared with cutaneous melanomas.10,11 Data for VVMs are scarce. The gene discussed is PDCD1; the disease is mucosal melanoma.