The Second Department of Thoracic Surgery is a clinical surgical department primarily focused on the comprehensive diagnosis and treatment of thoracic tumors. Established in 1976 as a thoracic surgery specialty group within the Department of Tumor Surgery at the institute's founding, it has since grown and developed under the leadership of esteemed predecessors such as Professor Zhang Lijian and Professor Yang Yue. Currently, the department has 33 beds, with a medical team of 42 members, including 18 physicians, 22 nurses, and 2 research personnel. Among the physicians, there are 6 senior-level specialists (chief physicians), 5 associate senior-level specialists, 8 attending physicians, and 1 resident physician, with 18 holding doctoral degrees. The department includes 4 doctoral supervisors, 3 master's supervisors, 1 national-level talent, 3 Beijing Science and Technology Rising Stars, and 2 individuals supported by the Beijing Association for Science and Technology's talent program. Integrating clinical care, education, and research, the department focuses on the clinical diagnosis and treatment of lung and esophageal malignancies, while actively advancing clinical and research efforts in mediastinal tumors, chest wall tumors, and pleural tumors. The department excels in complex major surgeries, including: tracheal and bronchial sleeve resection with reconstruction in lung cancer surgery, pulmonary angioplasty, carinal tumor resection and reconstruction, radical esophagectomy with various digestive tract reconstructions, resection of giant mediastinal tumors with vascular grafting and reconstruction, intrapericardial pneumonectomy, and resection of giant chest wall tumors with chest wall reconstruction. It is one of the earliest centers in China to advocate and adhere to standardized surgical treatment for lung cancer, contributing to the formulation of China's Ministry of Health guidelines for standardized lung cancer treatment. The department was among the first in China to adopt minimally invasive surgeries such as thoracoscopic lung cancer resection, McKeown esophagectomy, Ivor-Lewis esophagectomy, and mediastinal tumor resection, achieving advanced domestic technical levels. It also pioneers emerging surgical approaches, including subxiphoid mediastinal tumor resection and mediastinoscopic esophagectomy. The department consistently adheres to the coordinated development of clinical care, education, and research, guiding clinical practice with scientific research. It actively promotes the concept of individualized comprehensive treatment for lung and esophageal cancers, with surgery as the cornerstone, and continuously conducts clinical studies on perioperative novel drugs to ensure long-term survival for thoracic tumor patients. Additionally, leveraging cutting-edge technologies such as artificial intelligence, large language models, and digital diagnostics, the department manages the entire process of lung cancer patient care. Through a comprehensive decision-support system, it addresses the limitations of human cognitive capacity and the challenges of rapid knowledge updates in diagnosis and treatment. The department has produced numerous significant outcomes in areas such as clinical research on novel drugs for thoracic tumors, early diagnosis of thoracic malignancies, and the development of biomarkers for clinical efficacy and prognosis. The department maintains active international academic exchanges, fostering close relationships with multiple international academic organizations. It actively participates in major international conferences to share research findings and has hosted visits from leaders of international academic bodies and editors-in-chief of prominent journals. The department also actively engages in national missions to support Xinjiang and Tibet, deploying several key personnel to participate in the management and clinical work of the National Cancer Regional Medical Centers in Inner Mongolia and Yunnan.