Chemoimmunotherapy With or Without SBRT Before Surgery for Locally Advanced Oral and Oropharyngeal Cancer

Inclusion Criteria: 1. Oral/oropharyngeal squamous cell carcinoma confirmed by histology and/or cytology. 2. Clinical stage: resectable oral/oropharyngeal squamous cell carcinoma stage III-IVa (AJCC 8th edition) 3. Age: 18-65 years old. 4. According to the Eastern Cooperative Oncology Group (ECOG) criteria (performance status score of 0 or 1). 5. Good organ function: A. Hematology: WBC ≥ 4000/μL, neutrophil ≥ 2.000/μL, hemoglobin ≥ 9g/dL, platelet ≥ 100000/μL; B. Liver function: bilirubin ≤ 1.5 times the upper limit of normal (ULN) (patients with known Gilbert's disease and serum bilirubin level ≤ 3 times ULN can be included), AST and ALT ≤ 3 times, and alkaline phosphatase ≤ 3 times ULN; albumin ≥ 3g/dL; C. International normalized ratio (INR) or prothrombin time (PT) or activated partial thromboplastin time (aPTT) ≤ 1.5 times; D. Renal function: serum creatinine ≤ 1.5 times ULN or creatinine clearance ≥ 60mL/min according to the Cockcroft-Gault formula. 6. Expected survival ≥ 3 months. 7. The patient has signed an informed consent form and is willing and able to comply with the study visits, treatment plans, laboratory tests and other study procedures. 8. Women of childbearing potential must have a negative urine or serum pregnancy test within 7 days before enrollment and must agree to take effective contraceptive measures during the study and for at least 60 days after the last dose (including chemotherapy drugs and Teplizumab). 9. If the female partner of the male subject is still of childbearing potential, the male subject must agree to take effective contraceptive measures during the study and for at least 60 days after the last dose. Exclusion Criteria: 1. Patients with other malignant tumors. 2. Patients with known or suspected autoimmune diseases, including dementia and epilepsy. 3. Patients with severe mental illness. 4. Patients with necrotic lesions and who are assessed by the researchers to be at risk of major bleeding. 5. Patients with severe heart disease, pulmonary dysfunction, heart function and pulmonary function below grade 3 (including grade 3). 6. Patients whose laboratory test values do not meet the relevant standards within 7 days before enrollment. 7. Patients who have received systemic or local glucocorticoid treatment within 4 weeks before enrollment. 8. Patients with complications that require long-term use of immunosuppressive drugs or systemic or local use of corticosteroids with immunosuppressive effects. 9. Patients with active pulmonary tuberculosis (TB) who are currently receiving anti-tuberculosis treatment or have received anti-tuberculosis treatment within 1 year before screening. 10. Previous use of anti-toripalimab, anti-PD-L1 antibody, anti-PD-L2 antibody or anti-CTLA-4 antibody (or any other antibody acting on T cell co-stimulation or checkpoint pathway). 11. Subjects with any active autoimmune disease or history of autoimmune disease (including but not limited to: interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, nephritis, hyperthyroidism, hypothyroidism; patients with vitiligo or complete remission of asthma in childhood and no need for any intervention as adults can be included; patients with asthma requiring medical intervention with bronchodilators cannot be included). 12. HIV positive. 13. HBsAg positive and HBVDNA copy number positive (quantitative detection ≥1000cps/ml); positive blood screening for chronic hepatitis C (HCV antibody positive). 14. Any anti-infection vaccine (such as influenza vaccine, varicella vaccine, etc.) received within 4 weeks before enrollment. 15. Women of childbearing age with positive pregnancy test and breastfeeding women.