CD274 and head and neck squamous cell carcinoma: Our findings that Sema4D+ve/high represented 46 cases (34%) of the current HNSCC cohort, out of which 30 cases (65%) were PD-L1-ve/low, indicates that Sema4D+ve/high tumors, represent a significant subgroup of HNC that might be responsive to Sema4D inhibition as a monotherapy, specifically and PDL-1 negative tumors correlated with poor prognosis in certain stage III malignancies [84].