PD1 (Programmed cell death 1) and PDL1 (Programmed cell death ligand 1) inhibitors, are immunosuppressors of T lymphocytes, impair their function and promote tumor proliferation and invasiveness (68), and their antagonists are used in the treatment of cancers, including the anti-PD1-directed monoclonal antibody products nivolumab, pembrolizumab and durvalumab, and the anti-PDL1-directed atezolizumab and avelumab (69), which specifically target and destroy tumor cells. Here, PDCD1 is linked to cancer.