CD274 and small cell lung carcinoma: In the whole population (n = 1553, data available for all the four eligible trials), the addition of a PD-1/PD-L1 ICI to platinum-etoposide chemotherapy in patients with ES SCLC was associated with a statistically significant benefit in progression-free survival (HR 0.75, 95% CI 0.68–0.84, p < 0.00001) (Figure 1).