Although multiple immune-checkpoint inhibitors (ICIs) have demonstrated efficacy in recurrent or metastatic squamous-cell carcinoma of the head and neck (R/M-SCCHN), outcomes in the locally advanced (LA-SCCHN) setting remain suboptimal, and treatment continues to pose a major therapeutic challenge. Incremental improvements in efficacy are still required, necessitating the development of more effective regimens. Whether combining an ICI with chemotherapy and nimotuzumab can confer additional clinical benefit in LA-SCCHN remains to be determined. Against this backdrop, we designed a single-arm, phase II, single-centre clinical trial to evaluate the efficacy and safety of sintilimab plus chemotherapy and nimotuzumab for patients with LA-SCCHN.