The primary objective of the perioperative study is to evaluate pathological complete response in resectable II-IIIB(N2) KRAS-mutated nonsquamous non-small cell lung cancer participants receiving tislelizumab plus platinum-based doublet chemotherapy.

Inclusion Criteria:

1. Able to provide written informed consent (ICF) and able to understand and comply with the study requirements and assessment schedule.
2. Male or female aged ≥18 years at the time of signing the ICF.
3. Histologically or cytologically confirmed stage II-IIIB (N2) non-squamous non-small cell lung cancer (NSCLC) (AJCC 8th edition).
4. With Known KRAS gene mutation.
5. Evaluated by medical and surgical discussion to be eligible for R0 resection with curative intent prior to study enrollment.
6. At least one measurable lesion as defined by RECIST v1.1.
7. Eligible to receive platinum-based doublet chemotherapy.
8. ECOG performance status score ≤ 1.
9. Adequate organ function during the screening period
10. Good cardiopulmonary function, meeting the requirements for surgical resection with curative intent.
11. Patients of childbearing potential must be willing to use effective contraception during the study and for 120 days after the last dose of tislelizumab.

Exclusion Criteria:

Patients meeting any of the following criteria are not eligible for enrollment:

1. Previously received any treatment for the current lung cancer, including radiotherapy and all systemic anti-tumor treatments, including chemotherapy, immunotherapy, targeted therapy, or anti-angiogenic therapy.
2. Presence of locally advanced, unresectable disease, regardless of disease stage or presence of metastases.
3. Received other approved systemic immunomodulatory agents (including but not limited to interferon, interleukin-2, tumor necrosis factor, thymosin α1, and thymalfasin) within 4 weeks prior to the first dose.
4. Used any herbal medicine to control cancer within 14 days prior to the first dose of the study drug.
5. Received live or attenuated live vaccines within 4 weeks prior to enrollment or expected to require live or attenuated live vaccines during the study or within 5 months after the last dose of tislelizumab.
6. Any condition requiring systemic corticosteroid therapy (prednisone or equivalent >10 mg/day) or other immunosuppressive therapy within 14 days prior to the first dose of the study drug, which the investigator believes may affect the study treatment.
7. Active autoimmune disease requiring systemic treatment, which the investigator believes may affect the study treatment.
8. Interstitial lung disease, non-infectious pneumonitis, or uncontrolled other diseases, including diabetes, pulmonary fibrosis, acute lung disease, etc., which the investigator believes may affect the study treatment.
9. History of major diseases or clinical manifestations that may affect organ system function, which the investigator believes may affect the study treatment.
10. Severe chronic or active infections requiring systemic antibacterial, antifungal, or antiviral treatment within 14 days prior to the first dose of the study drug (including tuberculosis infection, etc.).
11. Known history of human immunodeficiency virus (HIV) infection.
12. Previously undergone allogeneic stem cell transplantation or organ transplantation.