MDM2, as a major p53 regulatory factor, can regulate the expression of PD-L1 in tumor cells, such as melanoma through the p53-dependent MDM2 pathway, and the MDM2 inhibitors Nutlin-3 and APG-115 induce PD-L1 expression on the surface of tumor cells in a p53-dependent manner. This evidence concerns the gene MDM2 and neoplasm.