They are approved by FDA for thetreatment of different cancer types like melanoma, non-small-celllung cancer, renal cell carcinoma, urothelial carcinoma, liver cancer,and colorectal cancer.19 PD-L1 expressionon tumor cells can be considered a predictive marker of increasedinvasion and invasiveness, but several studies are ongoing to clarifythe mechanism of action of PD-L1 and its associated pathways. This evidence concerns the gene CD274 and melanoma.