Lung cancer is a common malignant tumor of the lung. In recent years, with the influence of smoking and various environmental factors, the incidence rate and death rate of lung cancer have been rapidly increasing worldwide, especially in industrially developed countries, and has become the first cause of cancer death among male patients. According to the different sites of lung cancer, lung cancer is clinically divided into two types: central lung cancer and peripheral lung cancer. The majority of lung cancers originate in the bronchi. The majority of lung cancers originate from the bronchial mucosa epithelium. Lung cancers are mainly classified into “small cell lung cancer” and “non-small cell lung cancer” based on the histological size and appearance of the cancer cells under the microscope. The latter mainly includes squamous cell carcinoma, lung adenocarcinoma and large cell lung cancer. Based on the similarity between lung cancer cells and normal cells, lung cancer cells are classified as highly differentiated, moderately differentiated, poorly differentiated, and undifferentiated, in order of increasing malignancy. Lung cancer is also highly diverse, and it is common for tumors to include several small and medium-sized classes of cancer cells. For example, adenosquamous carcinoma of the lung, carcinoid tumor, etc.