SBRT Followed by Neoadjuvant Chemoimmunotherapy of Sindilizumab Plus Docetaxel and Cisplatin for Locoregionally Advanced Squamous Carcinoma of Oral Cavity and Oropharynx

All eligible patients will receive SBRT (6Gy\*3 fractions, qod) to the primary site and metastatic lymph nodes. One week later, neoadjuvant chemoimmunotherapy of Sindilizumab (200mg) plus docetaxel (75mg/m2) and cisplatin (75mg/m2) will be administered every three weeks for three cycles. Then radical surgical resection will be performed and postoperative radiotherapy with or without chemotherapy will be supplemented according to the initial tumor staging and postoperative pathologic characteristics.