The emergence of immune checkpoint inhibitors (ICIs) have changed the pattern of anti-tumor therapy and brought new hope to the treatment of small cell lung cancer (SCLC). Currently, ICIs are most widely studied mainly include programmed death-1/ligand-1 and cytotoxic T-lymphocyte antigen-4. Altezumab is recommended for the first-line treatment of extensive SCLC, while pebrizizumab is recommended for the third-line treatment of extensive SCLC. There has been no breakthrough in the second-line and maintenance treatment of SCLC with ICIs.