Lung cancer is a malignancy that originates in the lung cells, typically caused by tobacco smoke. It is broadly classified into non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Symptoms include persistent cough, chest pain, and shortness of breath. Diagnosis involves imaging tests and biopsies, with treatment options such as surgery, radiation, chemotherapy, targeted therapy, and immunotherapy. Prevention includes smoking cessation and minimizing exposure to carcinogens. Ongoing research aims to enhance early detection and develop more effective treatments.