CD274 and small cell lung carcinoma: Of note, our data from CASPIAN indicate that PD-L1 IC expression ≥ 1% is more prevalent in ES-SCLC (25.8%) compared to PD-L1 TC ≥ 1% (5.7%), and thus PD-L1 on immune cells or immune cells themselves could be more important in driving clinical benefit with D ± T + EP in the subset of patients with PD-L1 TC/IC ≥ 1% in CASPIAN.