CD8 + T cells (also commonly known as cytotoxic T lymphocytes) are pivotal players in immune defense against infection, as well as tumor cells.  Upon activation, CD8+ T cells are the direct effector cells that target and eliminate the tumor cells through recognizing tumor‐associated antigens and initiating a robust cytotoxic response.  To escape from antitumor immunity, tumor cells are shown to secrete TEVs enriched with immunosuppressive molecules to target CD8+ T cells, thereby leading to T cell exhaustion and promoting cancer progression (Figures 2 and 3).[195]. This evidence concerns the gene CD8A and infection.