CD274 and small cell lung carcinoma: Second, the NCCN Guidelines for SCLC have approved that the PD‐L1 inhibitors combining chemotherapy could be a new standard first‐line treatment for ES‐SCLC patients, but owing to the inaccessibility of drugs or lack of reimbursement by medical insurance companies in China, only 22 SCLC patients received PD‐L1 inhibitors combined with chemotherapy in this study.