Treatment options for stage IV lung cancer mainly include radiotherapy, chemotherapy, targeted therapy and immunotherapy. Stage IV lung cancer is also known as advanced lung cancer, in which the cancer cells have already metastasized and spread to the distal organs and lymphatic system, and cannot be surgically resected, so the treatment mainly focuses on comprehensive treatment such as radiotherapy, chemotherapy, targeted therapy, and immunotherapy, to help prolong the survival period and improve the quality of life. To help prolong the survival period and improve the quality of life of patients, it depends on the type of pathology and gene mutation of patients. For example, if the patient has stage IV small cell lung cancer, he can use EP chemotherapy with local radiotherapy to achieve good therapeutic effect; if the patient has lung adenocarcinoma with gene mutation, he can be treated with targeted drugs such as erlotinib, afatinib and gefitinib. Non-small cell lung cancer stage IV can be treated with chemotherapy combined with PD-1 immunotherapy; small cell lung cancer stage IV can be treated with EP combined with PD-L1.