This exploratory phase II study is designed to enroll 36 patients with operable locally advanced head and neck squamous cell carcinoma(defined according to 8th teh edition of AJCC Guideline). The patients are given 3cycles of AK112(20mg/Kg per cycle) combined with AP regimen(platinum based chemotherapy), with a 3-week interval between each cycle (d1,d22,d43). After 3 cycles' therapy, if the volume of primary tumor decreases by over 50%,the range of resection operation will be conducted by the actual range of tumor, or else the surgery will be conducted by the original range of the tumor. The adjuvant radiation therapy would be conducted in 4-6 weeks after the surgery, while the adjuvant therapy of AK112 would be given in 21days after the surgery for 14 cycles. The process will continue until disease progression or uncontrolled toxicity. The primary endpoint is pCR(pathological complete response) and 2y-EFS; the secondary endpoint is MPR(Main pathological response)、ORR(objective response rate)、2y-OS(overall survival)、organ retention rate and safety assessment.