CD274 and hypopharynx squamous cell carcinoma: ELOS is a randomized, two-arm phase II study on organ preservation of the larynx in advanced laryngeal or hypopharyngeal squamous cell carcinoma (LHNSCC) in stage III, IVA/B, which are only resectable by total laryngectomy and have PD-L1 expression with CPS ≥ 1.