Abstract
Immune checkpoint inhibitors (ICIs) have achieved prominent efficacy in the treatment of numerous cancers, which is the most significant breakthrough in cancer therapy in recent years. However, ICIs are associated with a series of immune-related adverse events (irAEs). Pneumonitis is an uncommon but potentially fatal irAE. In the case reported here, a patient with advanced small cell lung cancer (SCLC) had rapid progression of disease following chemotherapy and received ICIs. The patient experienced severe immune-related hyperthermia followed by immune-related pneumonitis. Fortunately, a good clinical response was achieved after the patient received corticosteroids and tocilizumab.