Immunotherapy for lung cancer generally takes a long time to take effect, and most patients will take effect after 2~4 courses of treatment, which is about 40~80 days, but there are differences in the time of effect due to the different immune status of each patient. Immunotherapy refers to the activation of immune cells, which then plays the role of killing cancer cells, and the activation of the immune system needs a certain amount of time. The activation of immune system needs a certain period of time. Different immunotherapeutic drugs, different usage and dosage also affect the onset of treatment. At present, the commonly used drugs in clinic are mainly immune checkpoint inhibitors, such as pembrolizumab, nabulizumab, etc. Currently, most of the immune drugs adopt 21 days as a treatment cycle, and the efficacy is usually evaluated after two cycles of immune therapy drugs are used. Lung cancer patients are recommended to visit professional hospitals and listen to doctors’ professional advice.