The in vitro and in vivo antitumor efficacy of PD-1-deficient CAR T cells against native PD-L1-expressing HCC and the effects of the CRISPR-mediated disruption of endogenous PD-1 on CD4 and CD8 subsets, and activation status of CAR T cells were studied. Here, PDCD1 is linked to hepatocellular carcinoma.