All the current FDA (US Food and Drug Administration)-approved cancer therapies targeting either PD-1 or PD-L1, such as Optivo® (nivolumab), Keytruda® (pembrolizumab), pidilizumab, and Libtayo® (cemiplimab) against PD-1, and Bavencio® (avelumab), Imfinzi® (durvalumab), and Tecentriq® (atezolizumab) against PD-L1, are associated with remarkable response rates in various cancers and have revolutionized cancer treatment. Here, PDCD1 is linked to cancer.