Lung cancer, particularly non-small cell lung cancer (NSCLC), remains a leading cause of cancer mortality worldwide. Immunotherapy, especially immune checkpoint inhibitors (ICIs) targeting PD-1, PD-L1, and CTLA-4, has revolutionized NSCLC treatment, showing promising efficacy and safety. Despite the benefits, challenges like adverse effects and cost-effectiveness persist. PD-L1 expression is a key biomarker for predicting immunotherapy response, yet a significant portion of patients with negative PD-L1 expression still benefit from certain immunotherapies. Ongoing research aims to optimize treatment strategies and identify predictive biomarkers for personalized therapy.