PDCD1 and neoplasm: By blocking the immune escape mechanism of the tumor, programmed death-ligand 1 or programmed cell death protein 1 inhibitors have been reported to have efficacy superior to conventional toxic chemotherapy, with a median OS exceeding 20 months in the first-line setting in some studies and a 1-year survival rate of nearly 70% in combination with platinum-based chemotherapy.28, 29, 30 Although none of the patients were administered ICIs for first-line treatment in this study, some patients who were treated after drug approval might benefit from second- or late-line ICI therapy.