In a systematic review of 23 trials comparing the adverse events of anti-PD1 vs. anti-PD-L1 in 3284 patients treated for non-small-cell lung cancer, the incidence of complications including colitis, hypothyroidism, hepatitis, and nephritis tended to be higher in the anti-PD-1 group (16% vs. 11%; p = 0.07) [36]. Here, PDCD1 is linked to hepatitis A virus infection.