Neoadjuvant Sacituzumab Govitecan Plus Tagitanlimab for Resectable Head and Neck Squamous Cell Carcinoma

Inclusion Criteria: * Aged 18 years and above, of any gender. * Histopathologically confirmed resectable head and neck squamous cell carcinoma (HNSCC), excluding nasopharyngeal, salivary gland, and thyroid malignant tumors; surgically assessed as resectable or potentially resectable. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0, 1, or 2. * Sufficient organ and bone marrow function, meeting the following: absolute neutrophil count (NEUT) ≥1.5×10⁹/L, platelet count (PLT) ≥80×10⁹/L, hemoglobin ≥8 g/dL; aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5×upper limit of normal (ULN), total bilirubin (TBIL) ≤1.5×ULN; serum creatinine (Cr) ≤1.5×ULN or creatinine clearance rate (CCR) \>60 mL/min; international normalized ratio (INR) ≤1.5, activated partial thromboplastin time (APTT) ≤1.5×ULN. * Voluntarily participate in the study, sign the informed consent form, and be able to comply with scheduled study visits and relevant procedures in the protocol. Exclusion Criteria: * A history of other malignant tumors within the past 5 years, except for cured and non-recurrent malignancies (e.g., basal cell carcinoma, cutaneous squamous cell carcinoma, superficial bladder cancer, cervical carcinoma in situ). * Active autoimmune disease or relevant medical history (except for type 1 diabetes mellitus under stable insulin therapy), including but not limited to immune neurological diseases, systemic lupus erythematosus, inflammatory bowel disease, autoimmune hepatitis, toxic epidermal necrolysis, or Stevens-Johnson syndrome. * A history of allergic diseases or severe drug allergy (anaphylaxis requiring hospitalization); known hypersensitivity to anti-PD-L1 antibodies, TROP2 antibody-drug conjugates (ADCs), or excipients of the study drugs. * Prior anti-tumor treatment involving anti-PD-1/PD-L1 antibodies, anti-CTLA-4 antibodies, TROP2 ADCs, or anti-tumor vaccine therapy. * Receipt of a live infectious vaccine within 4 weeks prior to the first dose or planned vaccination during the study period; major surgery or severe trauma within 4 weeks prior to the first dose. * Systemic use of corticosteroids (\>10 mg/day prednisone equivalent) or other immunosuppressants within 14 days prior to the first dose (inhaled or topical steroids and adrenal replacement therapy are permitted). * Severe medical conditions, including New York Heart Association (NYHA) class II or higher heart failure, ischemic heart disease, clinically significant arrhythmias requiring intervention, left ventricular ejection fraction (LVEF) \<50% on echocardiography, or prolonged QTc interval (males \>450 msec, females \>470 msec). * A known history of interstitial lung disease or high clinical suspicion of interstitial lung disease; active pulmonary tuberculosis or uncontrolled previous tuberculosis infection. * Hyperthyroidism or organic thyroid disease (patients with hypothyroidism under stable thyroid hormone replacement therapy are eligible for enrollment). * Active infection, unexplained fever within 48 hours prior to the first dose, or systemic antibiotic use within 1 week prior to signing the informed consent form. * Active hepatitis B (HBV DNA ≥2000 IU/ml or ≥10⁴ copies/ml), active hepatitis C (positive anti-HCV and HCV RNA above the lower limit of detection), positive HIV antibody, or a history of acquired immunodeficiency syndrome (AIDS). * A definite history of neurological or psychiatric diseases such as epilepsy or dementia. * A history of drug or alcohol abuse. * Pregnant or lactating females; patients (or their partners) planning pregnancy, having unprotected sexual intercourse, or refusing to take effective contraceptive measures during the study and for 3 months after study completion. * Receipt of other investigational drugs within 4 weeks prior to the first dose, or concurrent participation in other interventional clinical studies (observational or follow-up interventional studies are excluded). * Other circumstances deemed unsuitable for study participation by the investigator.