For patients with locally advanced head and neck tumors who are over 70 years old, have PS>2, have hearing impairment, renal dysfunction, or have neuropathy greater than grade 1 that is intolerant to cisplatin, radiotherapy alone or combined with EGFR monoclonal antibody radiotherapy should be chosen. The purpose of this study is to demonstrate the superior efficacy of Nitozumab and Sinilimab when added to radiotherapy in the treatment of high-risk participants with resected locally advanced squamous cell carcinoma of the head and neck (LA SCCHN) who are ineligible to receive cisplatin-based chemoradiation concurrently.