CD274 and small cell lung carcinoma: Notably, a single-arm phase II study using Pembrolizumab as maintenance therapy after chemotherapy in patients with ES-SCLC showed that patients with positive stromal PD-L1 had higher partial response (PR) (37.5% vs. 8.3%), longer mPFS (6.5 vs. 1.3 months), and mOS (12.8 vs. 7.6 months) compared to those with negative PD-L1.