Besides, there are clinical trials (NCT02867345, NCT02863913, NCT04417764, NCT03081715, NCT02867332) of CRISPR-mediated PD-1 gene knockout in patients with prostate cancer, bladder cancer, hepatocellular Carcinoma, advanced esophageal cancer and metastatic renal cell carcinoma associated with treatment [144]. Here, PDCD1 is linked to hepatocellular carcinoma.