Immune checkpoint inhibitors (ICIs) improved the prognosis of patients with advanced lung cancers. The combination therapy of cytotoxic drugs and ICI is approved as first-line chemotherapy in non-small-cell lung cancer (NSCLC) and extensive disease small-cell lung cancer (ED-SCLC). It has been reported various immune-related adverse events (irAEs). We herein report a 65-year-old man with NSCLC who developed hepatitis and pancreatitis simultaneously during the combination immunochemotherapy. In the treatment of hepatitis and pancreatitis, the clinical course was different. In this report, the importance of accurate diagnosis through detailed examination and treatment priority depending on the severity of the symptoms is indicated.