Extensive-stage small cell lung cancer (ES-SCLC) is a highly malignant disease with a poor prognosis. In the past few decades

although many clinical trials on new chemotherapy with its combinations and new biological agents were conducted

the overall survival rate has never been improved. The platinum-containing EP/EC chemotherapy regimen has always been the standard treatment method for ES-SCLC

however

the results of chemotherapy are not satisfactory

the median survival time and 2-year survival rate are only 7-10 months and 10%-20%

respectively. In recent years

there have been new advances in the combined immunotherapy for ES-SCLC

breaking the previous treatment bottleneck. The comprehensive genomic analysis of ES-SCLC shows that p53 (90%) and Rb1 (65%) are inactivated in most ES-SCLC patients. These gene mutations lead to the instability of the genome

causing ES-SCLC to have a high mutation load due to production of persistent related antigens by the tumor

thus laying the foundation for immunotherapy. We reviewed and analyzed the recent literature and discussed the combined immunotherapy regimens of ES-SCLC and ongoing clinical trials. We also reviewed the current exploration of combined immunotherapy model for ES-SCLC.