CD274 and small cell lung carcinoma: In recent years, the addition of immunotherapy targeting the PD-1/PD-L1 axis to the EP backbone has slightly increased overall survival (OS) rates and tripled the 3-year outcomes for a small group of long-term responders.11, 12, 13 Nevertheless, existing intertumoral heterogeneity in SCLC tumors and the lack of targetable driver mutations make it difficult to treat SCLC patients effectively.2