The majority of grade 3 irAEs were hepatitis (n = 5/7, 71%, single-agent PD-1/PD-L1 n = 2; IDO-1 inhibitor, n = 2; combination PD-1 and CTLA-4 [single agents within 12 weeks of one another], n = 1), and the remaining two patients had colitis (single-agent PD-1) and pneumonitis (combination PD-L1 and CTLA-4). The gene discussed is IDO1; the disease is hepatitis A virus infection.