PDCD1 and hepatocellular carcinoma: NSCLC: non-small cell lung cancer; RCC: renal cell carcinoma; HCC: hepatocellular carcinoma; OS: overall survival; PFS: progression-free survival; ORR: objective response rate; PD-1: programmed death-1; PD-L1: programmed death ligand-1; irAEs: immune-related adverse events; *P: prospective; R: retrospective