TFIs improve the therapeutic efficacy of T-cell engagers. The sketch summarizes the main findings from the Zieger et al study. (Top) Continuous exposure of T cells (represented by the blue character) to BsAbs (in the backpack) leads to progressive impairment of their function, exhaustion, and ultimately, to their inability to kill tumor cells. (Bottom) Implementation of TFIs in the therapeutic program allows preservation of function, improves metabolic fitness, and overall favors long-term disease control. Professional illustration by Somersault18:24.