The study is a single center phase II trial. The purpose is to investigate both the efficacy and safety of chemotherapy combined with anti-PD-1 antibody Followed by chemoradiotherapy in locoregionally advanced hypopharyngeal cancer.

Inclusion Criteria:

1. Age: 18-75 years;
2. Hypopharyngeal squamous cell carcinoma confirmed by histopathology;
3. No distant metastases, stage III-IV (According to the 8th UICC/AJCC TNM staging system );
4. At least 1 measurable lesion (according to RECIST1.1), and the lesion has not been treated;
5. Provide tissues for biomarker analysis;
6. ECOG PS 0-1;
7. Adequate hematologic, hepatic and renal function: ANC ≥ 1.5x10^9/L, Hb ≥ 90g/L, PLT ≥ 100 x10^9/L, albumin ≥ 28g/L, total bilirubin < 1.5×ULN at diagnosis or after biliary drainage, ALT and AST < 5×ULN, BUN、CREA<1.5×ULN, creatinine clearance rate ≥ 45ml/min;
8. Contraception during the study;
9. At least 12 weeks of life expectancy;
10. Willing to join the study and sign informed consent.

Exclusion Criteria:

1. Allergic to any component of carrelizumab, cisplatin and other platinum drugs;
2. Have received anti-PD-1, anti-PD-L1, anti-PD-L2, anti-CD137 or CTLA-4 antibody therapy in the past;
3. Received biological treatment or participated in clinical trial of other drugs or devices within 4 weeks before enrollment;
4. Have other malignant tumors within 5 years, except for fully treated basal cell/squamous cell skin cancer/cervical cancer;
5. Have corticosteroids (>10 mg prednisone equivalent dose per day) or other immunosuppressive agents for systemic treatment within 2 weeks before the first use of the study drug, except for local inflammation and prevention of allergies, nausea or vomiting;
6. Uncontrolled clinical symptoms or diseases of the heart, such as: heart failure above NYHA II, unstable angina, myocardial infarction within 1 year；
7. Have severe infections (CTCAE> Grade 2) occurred within 4 weeks before the first use of the study drug;
8. Have active autoimmune diseases, autoimmune diseases, but not including autoimmune-mediated hypothyroidism treated with stable doses of thyroid replacement hormone; type 1 diabetes with stable doses of insulin; vitiligo or cured childhood asthma/allergies;
9. A history of immunodeficiency, including a positive HIV test, or other acquired or congenital immunodeficiency diseases, or a history of organ transplantation and allogeneic bone marrow transplantation;
10. A history of interstitial lung disease (excluding radiation pneumonia that has not been treated with hormones) and a history of non-infectious pneumonia;
11. Active tuberculosis, having antituberculosis therapy at present or within 1 year;
12. Have active hepatitis B (HBV DNA ≥2000 IU/mL or 10~4 copies/mL) and hepatitis C;
13. Have other uncontrollable comorbidities;
14. Knowing a history of psychotropic drug abuse, alcohol or drug abuse;
15. Pregnant or breastfeeding, or expect to become pregnant during the clinical trial period.