The first point is that lung cancer can be categorized as a respiratory system disease, so one could visit the respiratory department. However, the respiratory department is not specialized enough for lung cancer, so it is recommended to visit the oncology department instead. After all, lung cancer is a malignant tumor. Initially, one can visit the respiratory department, but once it is confirmed through biopsy that it is lung cancer, it is advised to seek specialized treatment in the oncology department, as it is a malignant tumor.