Targeted drugs for the treatment of small cell lung cancer are currently approved in China in two main categories: 1. Anti-angiogenesis-based multi-target tyrosine kinase inhibitors, that is, anlotinib, are now approved for the third-line treatment of small cell lung cancer after recurrence, with an efficacy of about 3.4-3.5 months, which is relatively more convenient and safe than not. 2. The most important immune-targeted drugs are PD-1 and PD-L1 monoclonal antibodies, which are approved in China and recommended in the guideline, and PD-L1 monoclonal antibodies, also known as atrelicizumab, which has just been approved by the state, but not yet written into the guideline. These two drugs are currently available in our country in the third line of treatment.