This is a prospective, open-labelled study to evaluate the efficacy and safety of camrelizumab combined with apatinib mesylate in the induction treatment of patients with locally advanced head and neck squamous cell carcinoma who were judged surgically unresectable or appropriate for non-surgical definitive therapy. The objective response rate (ORR) and safety will be evaluated as the primary endpoints, the 2-year overall survival (OS) rate and progression free survival (PFS) rate will be the second endpoints.

Inclusion Criteria:

1. Histologically or cytologically confirmed squamous cell or poorly differentiated or undifferentiated cancer of the head and neck (the primary sites include oral cavity, oropharynx, hypopharynx, larynx, nasal cavity and sinuses);
2. Clinical stage of III-IVb (AJCC 2018);
3. Surgically unresectable and/or refuse surgery or appropriate for non-surgical definitive therapy;
4. Measurable disease;
5. Eastern cooperative oncology group performance status (ECOG PS) score: 0-1;
6. Blood routine: white blood cells> 3,000/mm3, hemoglobin> 8g/L, platelets> 80,000/mm3；Liver function: Alanine Transaminase/Aspartate Transaminase <2.5 times the upper limit of normal, bilirubin <1.5 times the upper limit of normal; Renal function: serum creatinine <1.5 times the upper limit of normal;
7. Sign the informed consent.

Exclusion Criteria:

1. Patients with poor-controlled arterial hypertension (systolic pressure ≥ 140 mmHg and/or diastolic pressure ≥ 90 mm Hg) despite standard medical management;
2. Suffered from grade II or above myocardial ischemia or myocardial infarction, uncontrolled arrhythmias (including QT interval male ≥ 450 ms, female ≥ 470 ms). Grade III-IV cardiac insufficiency according to New York Heart Association (NYHA) criteria or echocardiography check: left ventricular ejection fraction (LVEF)<50%;
3. Has had another active malignancy within the past five years except for cervical cancer in site, in situ carcinoma of the bladder or non-melanoma carcinoma of the skin;
4. Clinically significant and uncontrolled major medical conditions including but not limited to: active uncontrolled infection, symptomatic congestive heart failure, Unstable angina pectoris or cardiac arrhythmia, psychiatric illness/ social situation that would limit compliance with study requirements; any medical condition, which in the opinion of the study investigator places the subject at an unacceptably high risk for toxicities;
5. Patients undergoing therapy with other investigational agents;
6. Women who are pregnant or breastfeeding;
7. Patients with any other concurrent disease which, in the judgment of the investigator, would make the patient inappropriate for participation in the study.