GZMB and head and neck squamous cell carcinoma: GZMB, which encodes the pro-apoptotic enzyme granzyme B, was highly expressed in pDCs (Fig. 3c), suggesting that the cells in this population may exhibit GZMB-dependent cytotoxicity.30 Interestingly, a relatively high proportion of pDCs was observed in our scRNA-seq data (2% in all cells, and 16% in myeloid cells) compared to other cancer types (1%, 3%, and 10% in myeloid cells for lung cancer,13 breast cancer,31 and HNSCC,32 respectively).