PDCD1 and neoplasm: PD-1/PD-L1, TIGIT, and TGFβ all contribute to the suppressive function of Tregs and disruption of these pathways has been employed to modulate Treg activity.47 While the αTIGIT + bintrafusp alfa treatment neither decreased Treg populations nor improved CD8:Treg ratio in the MC38-CEA and TC1 tumor models, it decreased the TIGIT:CD226 ratio on tumor infiltrating Tregs in both models.