A 75-year-old man received first-line nivolumab (treatment dose, 360 mg every 3 weeks) plus ipilimumab (1 mg/kg intravenously every 6 weeks), combination therapy with anti-programmed cell death 1 (anti-PD-1) antibody, and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) antibody for malignant pleural mesothelioma. The gene discussed is PDCD1; the disease is malignant pleural mesothelioma.