ALK and lung cancer: In recent years, targeted therapeutic drugs such as epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKIs) and anaplastic lymphoma kinase (ALK) inhibitor, as well as immunotherapy drugs targeting programmed cell death protein 1 or programmed death ligand 1, have greatly improved the therapeutic effect of lung cancer and provided additional treatment options for patients with advanced and refractory lung cancer [24].