In addition, CCL5 deficiency upregulates PD-1 and PD-L1 expression and reduces resistance to anti-PD-1 antibody therapy in a mouse model of CRC (35)(Table 1 NO.4), The contradiction between PD-L1 expression and the above results may be due to in vivo experiments and the presence of more influential variables in CCL5-deficient transgenic mice, so more in-depth studies will be warranted to elucidate this discrepancy. The gene discussed is CCL5; the disease is colorectal carcinoma.