Recent findings have shown that hypermethylation of the PD-L1 promoter is associated with poor overall survival (OS) and recurrence-free survival (RFS) and can be considered an independent prognostic factor in several malignances such as colorectal cancer, prostate cancer, acute myeloid leukemia (AML) and melanoma [22,23,24,25]. This evidence concerns the gene CD274 and melanoma.