Lung cancer is one of the malignant tumors and falls under respiratory system diseases. The gold standard for the diagnosis of malignant tumors is biopsy. Thus, lung cancer is no exception; it requires a biopsy and immunohistochemistry to determine the type of cancer and its pathological type. So how is the biopsy obtained? We can use a bronchoscope to directly observe the tumor and collect small tissue samples for pathological examination. Additionally, there is the thoracic wall lung puncture biopsy, where tissue from the tumor can be sampled using a fine needle. These samples are observed under a microscope to differentiate the pathological types and to further confirm the diagnosis.