Inclusion Criteria:  Males and females ≥18 years of age. ECOG Performance Status 0 or 1. Histological diagnosis of squamous cell carcinoma of the lip, oral cavity, oropharynx, hypopharynx, larynx or nasal sinus. Stage III, IVa, IVb (according to the 8th AJCC edition); Stage III for HPV positive oropharyngeal disease. Inoperable or refused surgery; eligible for definitive concurrent chemoradiotherapy. With measurable target lesions by CT or MRI. Adequate bone marrow function. Adequate renal and liver function. Pregnancy test (for patients of childbearing potential) negative at screening. Signed Written Informed Consent.  Exclusion Criteria:  Have a history of immunodeficiency, or have other acquired or congenital immunodeficiency diseases, or have a history of organ transplantation. Active autoimmune disease (Such as type I diabetes, vitiligo, psoriasis, patients who do not need immunosuppressive drugs do not need to be excluded). Has abnormal thyroid function, and the thyroid function cannot be maintained normal despite medical treatment. Pregnancy or breast feeding. Has a history of psychiatric substance abuse, alcoholism, or drug addiction. Prior therapy with a PD-1, anti-PD-Ligand 1 (PD-L1) or CTLA-4 agent. Has received a live vaccine within 4 weeks of planned start of study therapy. Has hepatitis B surface antigen (HBsAg) positive with HBV DNA copy number of ≥1000cps/ml or hepatitis C virus (HCV) antibody positive.