In terms of disease progression, a high expression of PD-L1 in tumor tissue seems to be a mild but not significant risk factor for CRC patients under the situation of anti-PD therapy (n=3 studies, HR 1.13, 95%CI 0.55–2.32, I2=41%, p=0.18) (Fig. 2B, Supplementary Figure 1D) [3, 47, 51]. This evidence concerns the gene CD274 and colorectal carcinoma.