AbstractPurpose:. Angiogenesis inhibitors are known to modify tumor immunity. Combination of angiogenesis inhibitors with immune checkpoint inhibitors has shown efficacy against many types of cancers, including non–small cell lung cancer (NSCLC). We investigated the feasibility of neoadjuvant therapy with pembrolizumab and ramucirumab, a VEGFR-2 antagonist for patients with PD-L1–positive NSCLC, and its influence on the tumor microenvironment.Patients and Methods:. Patients with pathologically proven, PD-L1–positive, clinical stage IB to IIIA NSCLC were eligible. Patients received two cycles of pembrolizumab (200 mg/body) and ramucirumab (10 mg/kg) every 3 weeks. Surgery was scheduled 4 to 8 weeks after the last dose. The primary endpoint was the major pathologic response rate by a blinded independent pathologic review. The sample size was 24 patients. Exploratory endpoints were evaluated to elucidate the effects of neoadjuvant therapy on the tumor microenvironment.Results:. The 24 eli