PDCD1 and hepatitis A virus infection: Compared with patients treated with chemotherapy alone, those treated with a PD-1/PD-L1 inhibitor plus chemotherapy were more likely to experience all-grade hepatitis (RR = 2.14, 95% CI = 1.29 to 3.55, P < 0.01) and high-grade hepatitis (RR = 5.24, 95% CI = 1.89 to 14.52, P < 0.01).