CD8A and neoplasm: Biomarkers of ICI responsiveness include an immune inflamed tumor phenotype, described as a gene signature of immune related genes (123), pre-existing anti-tumor CD8+ T cells (124), low levels of circulating immunoregulatory cells and cytokines such as IL-10 and TGFβ (125), and a high tumor mutational burden which leads to high levels of tumor associated neoantigens, presumably associated with neoantigen-specific T cells (126, 127).