Inclusion Criteria:
* Aged from 18 to 70 years old;
* Subjects must be histopathologically diagnosed with non-small cell lung cancer originating from the bronchus or lung;
* Clinically confirmed as locally advanced unresectable stage IIIA, IIIB, or IIIC non-small cell lung cancer according to the 9th edition of the AJCC Cancer Staging System;
* ECOG performance status score of 0-1;
* Adequate organ and bone marrow function (without blood transfusion or hematopoietic stimulating factor medication within 14 days before evaluation):
Blood routine: absolute neutrophil count ≥1.5×10⁹/L, platelet count ≥100×10⁹/L, hemoglobin ≥9.0 g/dL; Liver function: total bilirubin ≤1.5×ULN; ALT/AST ≤2.5×ULN; Renal function: serum creatinine ≤1.5×ULN, or creatinine clearance rate ≥40 mL/min (calculated by the Cockcroft-Gault formula); Adequate cardiac function with left ventricular ejection fraction (LVEF) \>50% detected by echocardiography;
* Capable of signing the informed consent form (ICF) and complying with all requirements and restrictions specified in the ICF and study protocol;
* Able to receive regular follow-up with good treatment compliance.
Exclusion Criteria:
* Patients with EGFR-sensitive mutations (L858R, 19Del) or ALK/ROS1/RET gene fusions;
* Patients who have received any anti-tumor treatment prior to the initiation of this trial;
* Pregnant or lactating women;
* Patients with a history of allergy to any of the following drugs: pucotenlimab, Becotatug Vedotin, platinum agents, taxanes, etoposide, and pemetrexed;
* Patients with a history of other malignant tumors within the past 5 years or with concurrent malignant tumors;
* Patients with uncontrolled clinical cardiac symptoms or diseases, including:
1. Heart failure of NYHA class II or above;
2. Unstable angina;
3. Myocardial infarction occurred within 1 year prior to enrollment;
4. Clinically significant supraventricular or ventricular arrhythmia requiring clinical intervention;
* Patients who have received any of the following treatments:
1. Administration of any investigational drugs before the first dose of study drug;
2. Concurrent enrollment in another clinical study, except for observational (non-interventional) clinical studies or the follow-up phase of interventional clinical studies;
3. Systemic treatment with corticosteroids (daily dose equivalent to more than 10 mg prednisone) or other immunosuppressants within 2 weeks before the first dose of study drug. Topical corticosteroids for local inflammation, allergy prevention or anti-emetic treatment are permitted. In the absence of active autoimmune diseases, inhaled or topical steroids and adrenal corticosteroid replacement therapy at a dose equivalent to more than 10 mg prednisone daily are allowed;
4. Vaccination with anti-tumor vaccines or live vaccines within 4 weeks before the first dose of study drug;
5. Major surgery or severe trauma within 4 weeks before the first dose of study drug;
* Patients with severe infection (CTCAE grade ≥2) within 4 weeks before the first dose of study drug, such as severe pneumonia requiring hospitalization, bacteremia, and infectious complications. Patients with active pulmonary inflammation indicated by baseline chest imaging, or with infectious signs and symptoms requiring oral or intravenous antibiotic therapy within 2 weeks before the first dose of study drug (prophylactic antibiotic use is excluded);
* Patients with active autoimmune diseases (including but not limited to interstitial pneumonia, colitis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism, and hypothyroidism). Patients with vitiligo or resolved childhood asthma/allergy without any intervention in adulthood are excluded from this criterion;
* Patients with a history of immune deficiency diseases, including HIV-positive status, other acquired or congenital immune deficiency diseases, or a history of organ or bone marrow transplantation;
* Patients with active pulmonary tuberculosis infection confirmed by medical history or CT examination, or with a history of active pulmonary tuberculosis infection within 1 year before enrollment, or with a previous history of active pulmonary tuberculosis infection more than 1 year prior that has not received standardized treatment;
* Patients with active hepatitis: HBV DNA ≥2000 IU/mL (or 10,000 copies/mL); or positive hepatitis C antibody with HCV-RNA level above the detection limit of the analytical method;
* Patients with a history of psychoactive drug abuse, alcoholism or drug addiction;
* Patients who are unable to understand or likely to fail to comply with the trial requirements;
* Patients deemed unsuitable for enrollment by the investigators.
