Effector CD8+ T cell activation is dependent on the recognition of an antigen-major histocompatibility complex (MHC) on a tumor cell; upon successful recognition, CD8+ T cells release granules that contain perforin, granzyme, and the Fas ligand into the immunological synapse to carry out effector functions (Figure 1A) (Iwahori, 2020). This evidence concerns the gene CD8A and neoplasm.