This retrospective, multicenter study included patients with advanced non–small cell lung cancer who were treated with immune-checkpoint inhibitors....Of 364 patients, 37 (10%) expressed vascular endothelial growth factor receptor 2 in immune cells and 165 (45%) in tumor cells....The objective response rate, progression-free survival and overall survival were significantly worse in patients treated with immune-checkpoint inhibitor monotherapy who expressed vascular endothelial growth factor receptor 2 in immune cells than those who did not (10% vs. 30%, p = 0.028; median = 2.2 vs. 3.6 months, p = 0.012; median = 7.9 vs. 17.0 months, p = 0.049, respectively).