A Study to Evaluate the Efficacy and Safety of Multiple Treatment Combinations in Patients with Locally Advanced Squamous Cell Carcinoma of Head and Neck

A study to evaluate the anti-tumor effects of neoadjuvant treatment with Atezolizumab monotherapy, and combination treatments, consisting of Atezolizumab+Tiragolumab, Atezolizumab+Tiragolumab+ immune-modulating stereotactic body radiotherapy (iSBRT), and Atezolizumab+Tiragolumab+Carboplatin and Paclitaxel in Patients with Locally Advanced Squamous Cell Carcinoma of Head and Neck