Studies have shown that [15] in the process of malignant tumor formation, Soluble immunosuppressive factors secreted by cancerous cells could inhibit CD4+T cell proliferation and differentiation, whereas CD8+T cells dominated by TS have increased reactivity, which in turn has a modulatory or suppressive effect on CD4+T cells, leads to a reduction in CD4+/CD8+ ratio, and leaving the immune microenvironment toward an immunosuppressive state. The gene discussed is CD8A; the disease is cancer.