The gut microbiota have been demonstrated to influence the differentiation and function of M2-tumor-associated macrophages (M2-TAMs), tumor-associated neutrophils (TANs), DCs, and CD8+ T cells by their products, such as LPS, polysaccharide-dextran, deoxycholic acid (DCA), and SCFAs (Zhao et al., 2021). The gene discussed is CD8A; the disease is neoplasm.