FAS and neoplasm: 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).