TIGIT and neoplasm: The co‐inhibitory receptor T‐cell immunoglobulin and ITIM domain (TIGIT) marks a population of Treg cells with enhanced suppressive capacity in tumours.130, 131 Interestingly, TIGIT+ Treg cells preferentially suppress Th1 and Th17 (but not Th2) cells, the former being important in anti‐tumour immunity.