CD8A and neoplasm: When H2-Eb1 upregulates expression, certain haplotypes (such as H2-Eb1d) promote the secretion of IL-17 and exacerbate intestinal inflammation [31], while the increased expression of H2-K1 enhanced the killing ability of CD8+ T cells, exerting a protective effect in viral infections (such as influenza) and tumor immunity [39].