The strong overlap of TIGIT and PD-1 expands the results of earlier studies demonstrating the coexpression of both proteins [9, 13], but also other checkpoint receptors such as Lag3 [27] and Tim3 [28, 29], in tumour infiltrating lymphocytes and is consistent with recent reports describing comparable properties for the TIGIT/CD155/CD226 regulatory pathway and the PD-1/PD-L1-immune checkpoint [16, 17, 30, 31]. Here, CD226 is linked to neoplasm.