CD274 and salivary gland carcinoma: There is scarce literature on the role of PD-L1 in salivary gland carcinomas and only few other studies analyzing prognostic relevance of PD-L1 expression in different types of salivary gland carcinomas1,6,21–23: Mukaigawa et al. used the same threshold of ≥1% for PD-L1 positivity and demonstrated PD-L1 expression in a slightly higher fraction (23%) of the patient’s tumor cells and a moderately lower rate (13%) of the patient’s tumor-infiltrating mononuclear cells1.