Abstract: Immune checkpoint inhibitors (ICIs) are currently one of commonly used antitumor drugs in clinical practice, but they may trigger immune checkpoint inhibitor-related pneumonitis (CIP), thereby affecting the clinical benefits of patients. This article systematically analyzed domestic and foreign literature and summarized the research progress in the incidence, risk factors, pathogenesis, clinical manifestations, diagnosis, grading, and treatment of CIP. The paper aimed to timely intervene the occurrence and development of CIP and provided a reasonable and effective theoretical basis for the clinical application of ICIs.