There was a statistically significant positive correlation between PD-L1 intensity and CD3+, CD4+, or CD8+ tumour-infiltrating lymphocytes (TILs) (Fig. 1c), consistent with the known role of T cell-derived cytotoxicity as a driver of PD-L1 expression.52 Among the 29 cases (31.6%) showing PD-L1 staining, PD-L1 was mostly expressed on tumour cell surface (29.5%) and only sporadically detected in immune cells (2.1%; Fig. 1d). This evidence concerns the gene CD8A and neoplasm.