Immunotherapy for lung cancer is an emerging treatment tool, and it is more effective for some tumor patients, but not all lung cancer patients can undergo immunotherapy. However, not all lung cancer patients can be treated with immunotherapy. Currently, the popular immunotherapy drugs for lung cancer are PD-1 or PD-L1 inhibitors, and if patients want to apply immunotherapy, they should first undergo in vivo testing to check whether their tumors have PD-L1 overexpression. However, if the expression level is low, immunotherapy combined with chemotherapy can be considered. Immunotherapy has its side effects, so if the patient has autoimmune disease or serious heart, lung, liver or other serious diseases in the body, it is important to consult a professional doctor whether immunotherapy can be applied. Because some immunotherapy patients once applied immunotherapy may cause serious side effects, and even can cause the patient to die.