LAG-3 has previously been described on different T cell subsets,54–56 including Treg cells [Foxp3+CD25hiCD127lo],46,51,57 Tr1 cells [Foxp3−CD25loIL-10+],48,49,58,59 and exhausted tumour infiltrating lymphocytes [CD8+PD-1+],60 as well as NK cells53 and B cells.61 These studies have largely been conducted in murine models or using healthy human blood or tissue. This evidence concerns the gene PDCD1 and neoplasm.