Mid-stage lung cancer refers to hilar lymph node metastasis, which is a lymph node metastasis of N1. With N1 lymph node metastasis, the 5-year survival rate of patients after surgical resection is 40%-50%. Once combined with hilar lymph node metastasis, postoperative adjuvant chemotherapy or targeted therapy is also required. Of course, genetic testing is required before doing targeted therapy, and if genetic testing reveals genetic mutation or ALK gene mutation, treatment such as gefitinib, erlotinib or crizotinib can be performed. After surgical resection of mid-stage lung cancer, chemotherapy is also needed, which mainly uses platinum-containing 2-drug regimens. Chemotherapy has clear benefits in reducing recurrence and prolonging the total existence of patients.