Weight gain after immunotherapy for squamous lung cancer may be caused by disease control or aggravation of disease with ascites. 1. The condition is under control, immunotherapy is a relatively new treatment method nowadays, with little side effect and outstanding overall treatment effect. If the condition of squamous lung cancer patients is effectively controlled through immunotherapy, the tumor will no longer consume energy of human body, and after the nutrition is up to date, their weight will gradually increase and their body functions will be restored. 2. Ascites, if immunotherapy is ineffective, the condition continues to aggravate and abdominal metastasis occurs, and a large amount of ascites occurs, a large amount of fluid exists in the body, which will also lead to weight gain, so it is necessary to carry out drainage and perfusion treatment in time, and at the same time, carry out systemic chemotherapy and radiotherapy treatment.