Efficacy of Anti-CTLA-4 Antibody Combined With Sintilimab and Chemotherapy as Neoadjuvant Therapy for Resectable Stage II-III Non-Small Cell Lung Cancer

This study tests whether adding two immunotherapy drugs (anti-CTLA-4 antibody and sintilimab, a PD-1 inhibitor) together with standard chemotherapy before surgery improves outcomes for patients with surgically removable Stage II or III non-small cell lung cancer (NSCLC) that does not respond to PD-L1 immunotherapy alone. **You may be eligible if...** - You are 18 or older with confirmed NSCLC that can be surgically removed (Stage II to IIIB, excluding N3) - Your tumor is PD-L1 negative - You have not received any prior cancer treatment (chemotherapy, immunotherapy, or radiation) - Your tumor does not have targetable mutations like EGFR or ALK - Your overall health and organ function are adequate **You may NOT be eligible if...** - You have active autoimmune disease or are on immune-suppressing medications - You have a history of serious lung inflammation (interstitial pneumonia) - You have had recent major surgery or another active cancer within the past 5 years - You have uncontrolled cardiovascular disease (recent heart attack, stroke, or severe heart failure) - You are pregnant or breastfeeding - You have active hepatitis B or HIV Talk to your doctor to see if this trial is right for you.