ALT improvement rate was used to assess the efficacy of MMF based on the Common Terminology Criteria for Adverse Events version 5.0.<h4>Results</h4>Among 4405 patients treated with immune checkpoint inhibitors, 151 (3.4%) developed ir-hepatitis requiring systemic steroids, of whom 123 had grade ≥ 2 ALT elevation. The gene discussed is GPT; the disease is hepatitis A virus infection.