PD-L1 and PD-L2 coexpression were highly congruent in ES-SCLC, with more than 85% of patients with tumors that were either double positive (both PD-L1 and PD-L2 CPS ≥1) or double negative (both PD-L1 and PD-L2 CPS <1). This evidence concerns the gene CD274 and small cell lung carcinoma.