Ensartinib is primarily used in the treatment of non-small cell lung cancer (NSCLC), particularly for patients whose cancer is driven by ALK (anaplastic lymphoma kinase) gene mutations. It works as an ALK inhibitor, targeting and blocking the activity of the ALK protein, which is involved in the growth and spread of cancer cells. This helps to slow down or stop the progression of the disease. Ensartinib is especially beneficial for patients who have developed resistance to other ALK inhibitors, offering a therapeutic option for those with limited alternatives. It is administered orally, making it convenient for long-term use in managing advanced or metastatic NSCLC. Clinical trials have shown its efficacy in improving progression-free survival and overall response rates in ALK-positive NSCLC patients.