CTLA4 and neoplasm: Doering et al. [46] found that T-bet was associated with different genes in PD-1high and PD-1int cells: in PD-1high cells, T-bet-associated genes included those associated with T cell exhaustion such as LAG3 and CTLA4. Therefore, PD-1 expression in heterogeneous T cell populations is driven by gene expression, consistent with the literature showing that T-bet and EOMES play a role in T cell differentiation following tumor antigen recognition.