Proliferation-competent Tcf1+ CD8 T cells in dysfunctional populations are CD4 T cell help independent.

T cell maintenance in chronic infection and cancer follows a hierarchical order. Short-lived effector CD8 T cells are constitutively replaced from a proliferation-competent Tcf1-expressing progenitor population. This occurs spontaneously at low levels and increases in magnitude upon blocking PD-1 signaling.