This research focuses on exploring biomarkers for the application of PD - 1/PD - L1 immune checkpoint inhibitors in the perioperative immunotherapy of lung cancer. Multi - index tests are conducted on tissues prior to treatment, as well as blood samples at baseline and during the treatment course. The goal is to identify biomarkers capable of predicting the efficacy of neoadjuvant and adjuvant immunotherapies. Additionally, by integrating these multiple - index data into models, patients are to be stratified based on their potential benefits from perioperative immunotherapy, providing personalized guidance for clinical decision - making.

Inclusion Criteria:

• NSCLC, clinical tumor stage II-IIIB
• Without EGFR/ALK gene mutation
• Patient 18 years or older.
• Scheduled for neoadjuvant immunotherapy.
• Eastern Cooperative Oncology Group (ECOG) performance status score 0-1
• Life expectancy ≥ 12 weeks.
• Patient able to understand and sign written informed consent.

Exclusion Criteria:

• With other cancers (excluding NSCLC or skin cancer other than melanoma, or cancers treated curatively with follow up of more than 5 years without recurrence).
• With history of chemotherapy or radiotherapy (including pre - operative and post - operative adjuvant chemotherapy and radiotherapy) or systemic anti - tumor treatment.
• with autoimmune diseases unsuitable for PD - 1 monoclonal antibody treatment, including but not limited to myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, antiphospholipid syndrome, Wegener's granulomatosis, Sjogren's syndrome, Guillain - Barré syndrome, or multiple sclerosis.
• Patients who are unlikely to comply with the protocol (e.g. uncooperative attitude), inability to return for subsequent visits) and/or otherwise considered by the Investigator to be unlikely to complete the study.

Patients with non - small cell lung cancer who are negative for driver genes such as EGFR and ALK and receive neoadjuvant immunotherapy