PABLIXIMAB as Neoadjuvant Therapy for Head and Neck Squamous-cell Carcinoma

The goal of this clinical trial is to learn about the efficacy and safety of pablizumab combined with neoadjuvant chemotherapy in patients with locally advanced head and neck squamous cell carcinoma. The main question it aims to answer is: Pathological complete remission (PCR) rate of tumor after neoadjuvant immunotherapy. Participants will be asked to perform CT and MRI of head and neck, ultrasonography of cervical lymph nodes and necessary laboratory examinations Before and after neoadjuvant therapy. And will be following-up for at least 1 year.