This study is an open, prospective and observational clinical trial. Adopting a prospective cohort study design, it selects patients with non-small cell lung cancer who receive neoadjuvant immunotherapy as the research subjects. Through systematic follow-up, it monitors the dynamic changes of cortisol levels of patients at different treatment stages and after surgery, and analyzes the associations between these changes and disease progression, treatment effect and adverse reactions.

This is a single-center prospective observational cohort study. No experimental intervention will be performed on the participants, all clinical treatments and examinations are fully in accordance with the routine clinical diagnosis and treatment specifications for resectable non-small cell lung cancer. We only prospectively collect the clinical data and laboratory test results of the participants to analyze the correlation between perioperative dynamic changes of cortisol and the outcomes of neoadjuvant immunochemotherapy.

Inclusion Criteria:

1. Histologically confirmed primary non-small cell lung cancer (NSCLC), with clinical stage ⅡA-ⅢB resectable/potentially resectable disease, assessed according to the 8th edition of the American Joint Committee on Cancer (AJCC) TNM staging system.
2. Aged 18 to 75 years old, with Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
3. Planned to receive standard neoadjuvant PD-1/PD-L1 immune checkpoint inhibitor combined with platinum-based doublet chemotherapy, followed by radical surgical resection.
4. Have complete clinical data, and can complete the scheduled perioperative blood tests (including serum cortisol and ACTH level detection) and follow-up visits according to the study protocol.
5. Voluntarily participate in this study, sign the written informed consent form, and are willing to cooperate with the research team to complete the study-related examinations and follow-up.

Exclusion Criteria:

1. Patients with confirmed pituitary or adrenal diseases, or abnormal baseline serum cortisol/ACTH levels outside the normal reference range before enrollment.
2. Patients with a history of long-term systemic glucocorticoid use within 3 months before enrollment, or perioperative glucocorticoid use before the postoperative cortisol test.
3. Patients with a history of other primary malignant tumors within 5 years before enrollment (except for cured basal cell carcinoma of the skin or cervical carcinoma in situ).
4. Patients with severe autoimmune diseases, severe liver and kidney dysfunction, severe cardiovascular and cerebrovascular diseases, or other comorbidities that cannot tolerate neoadjuvant therapy and radical surgery.
5. Patients who did not receive radical surgical resection after neoadjuvant therapy.
6. Patients with incomplete clinical data, who cannot complete the scheduled blood tests or follow-up visits.
7. Pregnant or lactating women.
8. Patients with mental illness or other conditions that cannot comply with the study protocol.

This is a single-center prospective observational cohort study. The study population includes adult patients aged 18-75 years with histologically confirmed resectable stage ⅡA-ⅢB non-small cell lung cancer (NSCLC), who receive standard neoadjuvant PD-1/PD-L1 inhibitor combined with platinum-based chemotherapy followed by radical surgery in our center.