Lung cancer is the leading cause of cancer death globally, with the highest incidence and mortality rates in the United States and developed countries. The 5-year survival rate remains low at 15.6%, despite some improvements over the years. Tobacco smoking is the primary risk factor, with a 10-fold to 30-fold increased risk for lung cancer among long-term smokers compared to non-smokers. Other risk factors include occupational carcinogens, diet, and ionizing radiation. The incidence of lung cancer in never smokers, particularly women, is increasing, and genetic factors play a role in susceptibility. Gender differences exist, with women having a higher risk of lung cancer per unit of smoking exposure. Racial and ethnic variations also exist, with higher incidence and mortality rates among certain groups.Lung cancer is the leading cause of cancer death globally, with the highest incidence and mortality rates in the United States and developed countries. The 5-year survival rate remains low at 15.6%, despite some improvements over the years. Tobacco smoking is the primary risk factor, with a 10-fold to 30-fold increased risk for lung cancer among long-term smokers compared to non-smokers. Other risk factors include occupational carcinogens, diet, and ionizing radiation. The incidence of lung cancer in never smokers, particularly women, is increasing, and genetic factors play a role in susceptibility. Gender differences exist, with women having a higher risk of lung cancer per unit of smoking exposure. Racial and ethnic variations also exist, with higher incidence and mortality rates among certain groups.