Preclinical research has demonstrated that enriching beneficial microbial taxa, such as Lactobacillus, Bifidobacterium, Alistipes, and Ruminococcus, can stimulate anti-tumor immunity, enhance IL-12 production, and activate CD8+ T cells, thereby reshaping the tumor immune microenvironment toward a more immunostimulatory state [69,82,83,84]. The gene discussed is CD8A; the disease is neoplasm.