4 Courses vs 2 Courses of Pembrolizumab Combined With Carboplatin and Albumin-binding Paclitaxel of Neoadjuvant Therapy in HNSCC

Inclusion Criteria: * 18 years of age ≤65 years of age; * cytological or histological diagnosis of surgically resectable head and neck squamous cell carcinoma with the following stages: T3 or T4, N0; * According to the solid tumor efficacy evaluation criteria (RECIST version 1.1), there was at least one radiologically measurable lesion; First-line patients: have not previously received any systemic antitumor therapy for advanced/metastatic disease. Patients who had previously received platinum-containing adjuvant/neoadjuvant chemotherapy, or had received radical chemoradiotherapy for advanced disease, if the interval between disease progression or recurrence and the end of the last chemotherapy drug treatment was at least 6 months, were allowed to be enrolled in this study. * ECOG score 0-1; * Expected survival time \> 3 months; * Adequate organ function, subject shall meet the following laboratory indicators: 1. The absolute value of neutrophil granulocyte (ANC) ≥1.5x109/L in the last 14 days without the use of granulocyte colony stimulating factor; 2. Platelets ≥100×109/L without blood transfusion in the past 14 days; 3. Hemoglobin \&gt without blood transfusion or use of erythropoietin within the last 14 days; 9g/dL; 4. Total bilirubin ≤1.5× upper limit of normal value (ULN); 5. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5×ULN (ALT or AST ≤5×ULN in patients with liver metastasis); 6. Serum creatinine ≤1.5×ULN and creatinine clearance (calculated by Cockcroft-Gault formula) ≥60 ml/min; 7. Good coagulation function, defined as International Standardized ratio (INR) or prothrombin time (PT) ≤1.5 times ULN; 8. Normal thyroid function, defined as thyroid stimulating hormone (TSH) within the normal range. Subjects whose baseline TSH is outside the normal range can be enrolled if total T3 (or FT3) and FT4 are within the normal range; 9. The myocardial enzyme profile was within the normal range (if the researchers comprehensively judged that the simple laboratory abnormality was not clinically significant, it was also allowed to be included); 10. For female subjects of childbearing age, a urine or serum pregnancy test should be tested negative within 3 days prior to receiving the first study drug administration (day 1 of Cycle 1). If the urine pregnancy test results cannot be confirmed negative, a blood pregnancy test is requested. Women of non-reproductive age were defined as at least one year after menopause or having undergone surgical sterilization or hysterectomy; 11. If there is a risk of conception, all subjects (male or female) shall use contraception with an annual failure rate of less than 1% for the entire duration of treatment up to 120 days after the last study drug administration (or 180 days after the last chemotherapeutic drug administration). Exclusion Criteria: * Malignant diseases other than head and neck squamous cell carcinoma diagnosed within 5 years prior to initial administration (excluding basal cell carcinoma of the skin after radical treatment, squamous epithelial carcinoma of the skin, and/or carcinoma in situ after radical excision); * Currently participating in an interventional clinical study, or receiving other investigational drugs or using investigational devices within 4 weeks prior to initial dosing; * Previous treatment with anti-PD-1, anti-PD-L1, or anti-PD-L2 drugs or drugs that target another stimulus or synergistic inhibition of T cell receptors (e.g., CTLA-4, OX-40, CD137); * Systemic treatment with Chinese patent drugs or immunomodulatory drugs (including thymosin, interferon and interleukin, except for local use to control pleural effusion) with indications of anti-head and neck squamous cell carcinoma within 2 weeks before the first administration; * An active autoimmune immune disease requiring systemic treatment (e.g. with disease-modifying drugs, glucocorticoids, or immunosuppressants) has occurred within 2 years prior to initial administration. Alternative therapies (such as thyroxine, insulin, or physiologic glucocorticoids for adrenal or pituitary insufficiency) are not considered systemic therapy; * Was receiving systemic glucocorticoid therapy (excluding nasal, inhalation, or other routes of topical glucocorticoids) or any other form of immunosuppressive therapy within 7 days prior to initial administration; Note: Physiological doses of glucocorticoids (≤10 mg/ day of prednisone or equivalent) are permitted; * Clinically uncontrollable pleural effusion/abdominal effusion (patients with no need to drain effusion or no significant increase of effusion after 3 days of stopping drainage could be included in the group); * Known allogeneic organ transplantation (except corneal transplantation) or allogeneic hematopoietic stem cell transplantation; * Those who are known to be allergic to the active ingredients or excipients of the drug in this study, Pabolizumab, carboplatin and albumin-binding paclitaxel; * Has not fully recovered from toxicity and/or complications caused by any intervention before starting treatment (i.e., ≤ grade 1 or baseline, excluding weakness or hair loss); * Known history of human immunodeficiency virus (HIV) infection (i.e. HIV 1/2 antibody positive); * Untreated active hepatitis B (defined as HBsAg positive coupled with a detected HBV-DNA copy number greater than the upper limit of normal in the laboratory of the study center); Note: Hepatitis B subjects who meet the following criteria can also be enrolled:1) HBV viral load \&lt before initial administration; At 1000 copies /ml (200 IU/ml), subjects should receive anti-HBV therapy to avoid viral reactivation throughout the study treatment period.2) For subjects with anti-HBC (+), HBsAg (-), anti-HBS (-), and HBV viral load (-), prophylactic anti-HBV therapy is not required, but close monitoring of viral reactivation is required * Active HCV infected subjects (HCV antibody positive and HCV-RNA level above the lower