CD274 and small cell lung carcinoma: Our study firstly explored the four-drug regimen containing surufatinib for treatment-naive patients with ES-SCLC and it was the first study combined small molecule anti-angiogenic TKI plus anti-PD-1 antibody and platinum–etoposide doublet regimen for ES-SCLC, while the ETER701 study27 investigated antiangiogenic therapy plus anti-PD-L1 antibody and doublet chemotherapy for ES-SCLC.