CD274 and head and neck squamous cell carcinoma: The aim of the current study was to establish the concordance between the 22C3 antibody–based LDT and the gold standard PD-L1 IHC 22C3 pharmDx using CPS in five tumor types separately (cervical cancer [CC], ESCC, HNSCC, TNBC, and urothelial carcinoma [UC]) and together in a pan-tumor analysis.