There is no obvious breakthrough in treatment for small cell lung cancer (SCLC) in more than 30 years

and the prognosis has not improved significantly. With the opening of the immune era

immune checkpoint inhibitors have made breakthroughs in SCLC treatment

but the overall benefit population is limited. How to select patients accurately and how to increase the efficacy of immunotherapy are hot topics in SCLC research. Therefore

this article summarized the current status of SCLC with focus on biomarkers related to SCLC immunotherapy

reviewed the progress in the research of immunotherapy markers in recent years

to provide clues and ideas for future immunotherapeutic strategies.