Bioinformatics analysis further showed that CMTM6 expression was positively correlated with PD-L1 in CRC (P < 0.001) and CMTM6 expression correlated with M2 macrophage-related gene [CD163 (P < 0.001), CD206 (P < 0.001), IL-10 (P < 0.001), STAT3 (P < 0.001), IL-33 (P < 0.001)]. Here, IL33 is linked to colorectal carcinoma.