CD8A and cancer: HLA-I (MHC-I), of great importance, consists of a highly polymorphic α-heavy chain and a β2-microglobulin (β2M) light chain, encoded by the HLA-A, HLA-B, or HLA-C genes, delivers peptides to CD8+ T cells, and is essential for immune surveillance and cancer immunotherapy (Hazini et al., 2021).