The immunopathogenesis of cancer varies, but there are two main types of cancer in which the main effectors are CD8+ T cells specific to tumor antigens (i.e., neoantigens) can be divided into “T-cell-inflamed”, where antitumor T cells aggregate before treatment, and “non-T-cell-inflamed”, where such aggregation is absent. This evidence concerns the gene CD8A and neoplasm.