PDCD1 and cancer: Recently being granted approval by the Food and Drug Administration (FDA), immune checkpoint inhibitors anti-programmed cell death protein 1 (PD-1)/PD-L1 are the first drugs to demonstrate prognostic benefits for the treatment of platinum-refractory recurrent or metastatic HNSCC.16 Investigation of other immune checkpoint receptors as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) solely or in conjunction with other immunotherapies or conventional cancer therapeutics has been gaining more attention.