Induction PD-1 Inhibitor and Chemotherapy Followed by Chemoradiotherapy in Unresectable or Inoperable HPV-negative LA-HNSCC

The goal of this clinical trial is to evaluate if adding chemotherapy and immunotherapy as induction treatment prior to definitive chemoradiotherapy could improve the outcomes of locally advanced HPV-negative head and neck squamous cell that are not amenable to surgery. The study aims to answer: 1. Does this treatment improve the survival outcomes of participants? 2. How do the tumors of participants response to the treatment? 3. How is the safety of this treatment? Researchers will compare this treatment (induction chemoimmunotherapy, followed by concurrent chemoradiotherapy, and then immunotherapy as maintenance therapy) to concurrent chemoradiotherapy to see whether it provides additional clinical benefits.