TCF7 and neoplasm: Based on studies by Kamphorst et al. and Yost et al. showing that the tumor specific T cells in circulation have features of reinvigoration and less dysfunctional than their tumor counterparts, [33, 37] we hypothesize that expression of TCF7 by CD8 T cells from responders could indicate tumor-specificity and with the potential to be reinvigorated post PD-1/PD-L1 blockade.