Currently, the newest drugs for treating small cell lung cancer are immune checkpoint inhibitors, such as nabumab, pabolizumab, and divalizumab. Immune checkpoint inhibitors can make T-lymphocytes, which cannot act on tumor cells, act on tumor cells again, enhance patients’ immune system, and kill lung cancer cells through autoimmune system. 1. Nabumab: human immunoglobulin G4 monoclonal antibody targeting PD-1 can block the immune escape of tumor cells and enhance the ability of immune system to kill tumor cells. 2. Pabolizumab: another PD-1 monoclonal antibody drug with a similar mechanism of action as nabumab. 3. Duvarizumab: an immunosuppressant targeting PD-L1, the overall survival rate of some small-cell lung cancer patients is significantly improved after combined with chemotherapy. Patients with small cell lung cancer need to choose carefully what kind of drugs they need to use under the guidance of doctors and in combination with their own conditions, and should not use drugs blindly by themselves.