CD274 and small cell lung carcinoma: In line with these promising results, Keynote 028, a phase Ib trial tested the activity and safety of pembrolizumab (given at 10 mg/kg every 2 weeks) in 24 extensive-stage SCLC patients selected for PD-L1 expression (TPS ≥ 1%), who had failed at least one line of standard therapy [66].