Overcoming T cell exhaustion and senescence in CAR T cell therapy for solid tumors

Chimeric antigen receptor (CAR) T cell therapies have demonstrated remarkable efficacy in hematologic malignancies; however, their clinical benefit in solid tumors remains limited. A major barrier is T cell dysfunction, particularly exhaustion and senescence, which impair persistence, effector function, and durable tumor control. Targeting these dysfunctional states is therefore essential in order to improve CAR T cell efficacy in solid tumors.This review summarizes recent preclinical strategies aimed at preventing or reversing CAR T cell exhaustion and senescence in solid malignancies. While both exhaustion and senescence are relevant dysfunctional states, the preclinical evidence summarized in this review is currently more extensive for modulation of exhaustion-associated programs than for direct reversal of canonical T cell senescence. Approaches are organized according to their primary mechanistic focus, including gene editing, metabolic modulation, receptor redesign, and remodeling of the tumor microenvironment.Across these mechanistic categories, reported benefits include enhanced CAR T cell persistence, reduced expression of inhibitory receptors, such as PD-1, LAG-3, and TIM-3, preservation or restoration of memory-like phenotypes, and improved antitumor cytotoxicity. Notably, combinatorial strategies targeting multiple dysfunction pathways consistently demonstrate superior efficacy in preclinical models. Despite these advances, important translational challenges remain, including the limited predictive value of current preclinical systems, potential safety concerns, and the manufacturing complexity associated with increasingly engineered cell products.Collectively, preclinical evidence supports the rational integration of complementary approaches to generate next-generation CAR T cells capable of resisting dysfunction and maintaining activity within immunosuppressive solid tumor microenvironments. Further validation in clinically relevant models will be critical to facilitate translation into safe and durable cancer immunotherapies.