Abstract
Colitis is a common adverse event in patients treated with immune checkpoint inhibitor (ICI). Additionally, virus infections pose an increased risk during ICI therapy. Corticosteroids is the cornerstone in treatment for ICI-related colitis. We herein report a case that includes detailed endoscopic and pathological findings of a patient diagnosed with advanced non-small cell lung cancer who was co-infected with HBV and EBV and demonstrated significant improvement after treatment with oral methylprednisolone. Given the widespread use of ICI, physicians should be vigilant regarding various adverse events, and patients should be monitored closely during treatment with ICI. Endoscopic and pathological evaluation insights into the management of ICI-related colitis.