IFNG and head and neck squamous cell carcinoma: To demonstrate not only the efficacy but also the effects of the synergism/additivity or even antagonism of pembrolizumab alone, or in combination with cetuximab and the effects of IFN-γ, an ex vivo assessment of tumor cell colony formation (CFec) was conducted by utilizing histopathologically confirmed HNSCC samples in the FLAVINO assay (34).