In the clinic, disruption of the PD-1/PD-L axis using monoclonal antibodies (mAbs) directed at either the PD-1 receptor or ligands PD-L1 and PD-L2 has proven to be an effective and well-tolerated therapy for a range of tumor types such as metastatic melanoma, non-small-cell lung cancer, head and neck carcinoma, classic Hodgkin lymphoma, urothelial and renal carcinoma, cutaneous squamous carcinoma, and solid tumors confirmed to be microsatellite instability high (MSI-H) or mismatch repair deficient (dMMR) [10, 11]. This evidence concerns the gene PDCD1 and neoplasm.