In metastatic malignant melanoma (MM), anti-PD1 therapy has been proven as superior treatment to chemotherapy as first-line therapy and after ipilimumab (anti-CTLA-4 antibody) failure (Ribas et al., 2015; Weber et al., 2015) and in non-small cell lung cancer (NSCLC) patients after progression to first-line chemotherapy (Vokes et al., 2018). This evidence concerns the gene CTLA4 and metastatic melanoma.