CD274 and small cell lung carcinoma: Currently, several ICIs, such as atezolizumab, durvalumab, serplulimab and adebrelimab, which target the PD-1/PD-L1 pathway, have been approved for the treatment of ES-SCLC by the National Comprehensive Cancer Network (NCCN) or Chinese Society of Clinical Oncology (CSCO) guidelines.