Microbiota in Neoadjuvant Chemoimmunotherapy for NSCLC

Inclusion Criteria: 1. Age between 18 and 80 years; 2. Newly diagnosed, driver gene-negative non-small cell lung cancer (NSCLC) confirmed by histopathology (Stage IIA-IIIB); 3. At least one measurable lesion as defined by RECIST version 1.1; Eastern Cooperative Oncology Group (ECOG) performance status of 0-1; 4. No prior systemic therapy or radiotherapy; 5. Eligible for surgical resection and suitable for neoadjuvant immunotherapy or chemotherapy as determined by multidisciplinary evaluation; 6. Signed written informed consent prior to study participation; 7. Adequate pulmonary ventilation and diffusion function confirmed by pre-enrollment pulmonary function test to allow for surgical resection. Exclusion Criteria: 1. Requirement for systemic glucocorticoid therapy or other immunosuppressive treatments; 2. Use of antibiotics or presence of infections requiring antibiotic therapy within the past 3 months; 3. Probiotic use within 3 months prior to enrollment; 4. Presence of obstructive pneumonia, cancerous cavitation, or active pulmonary tuberculosis; 5. Presence of bronchiectasis, concurrent pulmonary infections, pulmonary fibrosis, or uncontrolled diabetes mellitus; 6. Presence of a primary tumor in another organ; 7. Receipt of chemotherapy or any other cancer treatment prior to enrollment; 8. Confirmed brain metastases by contrast-enhanced MRI before enrollment; 9. Active or pre-existing autoimmune diseases; 10. Uncontrolled comorbidities including heart failure, uncontrolled hypertension, unstable angina, or interstitial lung disease; 11. Positive for hepatitis B surface antigen or detectable hepatitis C RNA requiring treatment; 12. Known history or positive test for human immunodeficiency virus (HIV) or acquired immunodeficiency syndrome (AIDS); 13. Pregnant or breastfeeding women; 14. Previous treatment with anti-PD-1, anti-PD-L1, anti-PD-L2, or anti-CTLA-4 antibodies.