Lung cancer is a complication of chronic obstructive pulmonary disease (COPD), but it is relatively less common for COPD patients to also have lung cancer. Regular health check-ups, including annual lung CT scans, can help identify the possibility of cancerous changes at an early stage. In the early stages of lung cancer, patients generally do not show obvious clinical symptoms. As the disease progresses, symptoms such as coughing up blood, weight loss, fatigue, and night sweats may occur. However, since the clinical symptoms of lung cancer are similar to other lung diseases, there are no typical clinical features, and imaging studies are needed for preliminary screening.