There are many causes of pulmonary nodules, and the respiratory physician will improve the relevant tests according to the characteristics of the nodule. For example, when infectious pulmonary nodules caused by bacteria, fungi, or Mycobacterium tuberculosis are considered, the respiratory physician will treat them with sensitive anti-infective drugs. If old lesions or benign tumors are considered, the respiratory physician will also order regular review of the lung CT for dynamic observation. However, some lung nodules may be lung malignant tumors, so the respiratory physician will improve the corresponding examination, especially pathological biopsy, to clarify the diagnosis. For middle to late stage lung cancer, respiratory doctors will provide comprehensive treatment such as radiotherapy, chemotherapy and targeted drugs. If early stage lung cancer or malignant nodules cannot be ruled out, thoracoscopic surgery in conjunction with a thoracic surgeon is required to clarify the diagnosis and assist in treatment.