There are two main reasons for fever in the late stage of lung cancer: First, fever caused by cancer itself, because lung cancer is a malignant tumor, tumor cells will gradually die and destroy normal tissues, which will also lead to necrosis of normal tissue cells, and in the process of necrosis absorption, fever can occur, which is also called cancer fever. Secondly, because patients with advanced lung cancer often have poor body resistance and low immunity, they are prone to co-infection, especially respiratory tract infection. When co-infection occurs, fever may appear, which may cause high fever and even clinical symptoms such as cough and sputum, and corresponding anti-infection treatment should be given, such as cefuroxime and cefoperazone.