In many types of cancers, dysfunctional and exhausted CD8+ T cells have been found; this reduces the body’s defensive activity through the reduced formation of tumor necrosis factor (TNF), interleukin-2 (IL-2), and interferon-γ, which are important cytokines involved in the immune response [29,30].The interaction between the tumor microenvironment (TME) and CD8+ T lymphocytes favors the triggering of immunosuppressive mechanisms, including PD1 overexpression [31,32,33]. This evidence concerns the gene CD8A and cancer.