For example, the IMpower133 study demonstrated that adding atezolizumab (PD-L1) to chemotherapy for first-line treatment of ES-SCLC resulted in significant improvement in overall survival (OS, hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.60 to 0.95; p = 0.0154) and progression-free survival (PFS, HR, 0.77; 95% CI, 0.62 to 0.96; p = 0.02) versus chemotherapy (8, 9). This evidence concerns the gene CD274 and small cell lung carcinoma.