Efficacy Analysis of Neoadjuvant Treatment in Lung Cancer Using Low-dose Nivolumab Combined With Chemotherapy

Inclusion Criteria: * Able to provide a signed Informed Consent Form (ICF), indicating agreement to comply with the requirements and restrictions in the ICF and protocol. * Male or female, aged 18 years or older. * Diagnosed with non-small cell lung cancer (NSCLC) with clinical staging IB, II, or IIIA. * Receiving treatment at Hospital de Base. * Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 at enrollment, with no decline from two weeks prior to the baseline period or the day of the first dose. * Tumor sample meets the following requirements: * Negative for EGFR gene expression. * Negative for ALK and ROS1 protein expression. * PD-L1 protein expression documented and assessable. * Tumor is considered resectable upon initial assessment by three thoracic oncology surgeons (IR, CM, and HN) following a multidisciplinary review. * Adequate organ and bone marrow function as defined below: * Hemoglobin: ≥ 9.0 g/dL\* * Absolute neutrophil count: ≥ 1.5 × 10\^9 /L\* * Platelet count: ≥ 100 × 10\^9 /L\* * \*Note: Granulocyte colony-stimulating factor (G-CSF), platelet transfusions, and blood transfusions are not permitted to meet these values. * Serum bilirubin: ≤ 1.5 × upper limit of normal (ULN), except for participants with confirmed Gilbert syndrome, who may be included upon physician consultation. * ALT and AST: ≤ 2.5 × ULN. * Creatinine clearance: ≥ 50 mL/min (calculated using the Cockcroft and Gault formula). * Life expectancy greater than six months prior to randomization. Exclusion Criteria: * Refusal to sign the Informed Consent Form (ICF). * NSCLC clinical stages IA, IIIB N3, IIIC, IVA, and IVB. * Tumors with T4 invasion of the aorta, esophagus, and/or heart; or presence of bulky N2 disease. * Tumor deemed unresectable. * Prior systemic anticancer therapy for NSCLC, including chemotherapy, biologic therapy, immunotherapy, or any investigational drugs. * History of another primary malignancy, with exceptions for: * Malignancies treated with curative intent and no active disease for ≥ 2 years before the first dose of investigational product (IP) and with a low risk of recurrence. * Adequately treated non-melanoma skin cancer or lentigo maligna with no evidence of disease. * Adequately treated carcinoma in situ with no evidence of disease. * Incomplete basic medical information in the electronic medical record. * Positive for EGFR gene expression. * Positive for ALK protein expression. * No available data on PD-L1 protein expression. * Positive for ROS1 protein expression. * Pregnant or breastfeeding at the time of enrollment.