A previous study revealed that the inhibition of PD-1 enhances the phagocytosis of TAMs, thereby prolonging survival time in a mouse model of colon cancer.75 In addition, TAMs can interact with T cells and inhibit the antitumor immune response of T cells through the PD-1/PD-L1 signaling pathway. This evidence concerns the gene PDCD1 and malignant colon neoplasm.