PRF1 and head and neck squamous cell carcinoma: In addition, consistent with the emerging concept that blocking IFNα signalling may help to restore immune surveillance and enhance the effect of ICB.50,51 Our results showed that increasing PDL1 expression in tumour cells suppresses the release of granzyme M and perforin by NK cells to kill tumour cells, and that attenuating the IFNAR1/Stat1 signalling could enhance the NK cell-mediated cytotoxicity against HNSCC cells.