As shown in Fig. 4A–C, HHIP expression was markedly positively correlated with PD1, PD-L1, and CTLA-4 in CRC.Similar to TIMER data analysis, we discovered that there was striking positive correlation of HHIP with PD-L1, CTLA4 and PD1 in CRC (Fig. 4D-F). The gene discussed is PDCD1; the disease is colorectal carcinoma.