CD274 and neoplasm: Biological and technical challenges in immunohistochemically evaluating PD-L1 expression might explain, at least partially, PD-L1 status-therapeutic response discordances,11 because tumour and immune cells must be considered, and the latter are frequently PD-L1+.12 Moreover, other cells, e.g. CD8+ tumour-infiltrating T lymphocytes (TILs)13 or CD163+ histiocytes,14 that play important roles immune-response regulation, could be involved in immunotherapy efficacy.