As shown in Figures 6A,B, both the Akt activation status and the expression of anti-apoptotic protein Bcl-xL in PD-1 deficient GPC3-CAR T cells was significant (P < 0.001) increased compared with that in the wild-type GPC3-CAR T cells after 48 h of coculture with native PD-L1-expressing GPC3-positive PLC/PRF/5 HCC cells. Here, PDCD1 is linked to hepatocellular carcinoma.