PDCD1 and neoplasm: cbm588 can improve intestinal immune homeostasis by altering the intestinal flora, especially by increasing the abundance of ruminococcal bacteria, and effectively enhance the response to PD-1 blockade. cbm588 treatment promoted the expression of indoleamine 2, 3-dioxygenase 1 and IL-10 in the colon and enhanced the ability of lamina propria monocytes in tumor carriers to secrete IL-10. However, blocking the IL-10 signaling pathway enhances the ability of CD8+ T cells to secrete interferon -γ.