[Fatal opportunistic infection occurred during the treatment of immune checkpoint inhibitor-associated colitis:case report].

Immune checkpoint inhibitor (ICI) has been widely used in lung cancer patients. While ICI treatment improves the overall survival of patients, it can also lead to a series of immune-related adverse events (irAE). Severe irAE should be treated with glucocorticoids and biological agents. Opportunistic infections should be highly vigilant during the treatment of glucocorticoids and biological agents. We report a patient with locally advanced non-small cell lung cancer who developed severe ICI-related colitis after chemotherapy combined with immunotherapy. The patient developed hematogenous disseminated Mycobacterium tuberculosis infection and pulmonary aspergillosis during the treatment with glucocorticoids and biological agents (infliximab). The purpose of this study is to draw the attention of clinicians to opportunistic infections when dealing with irAE.