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). Here, PDCD1LG2 is linked to small cell lung carcinoma.