The Treg-cell death axis in lung cancer: implications for immune evasion and novel therapeutic strategies.

Regulatory T cells (Tregs) are central mediators of immune tolerance and key drivers of tumor immune evasion in non-small cell lung cancer (NSCLC). Within the tumor microenvironment (TME), Tregs accumulate and suppress antitumor responses, thereby limiting the durability of immune checkpoint inhibitor (ICI) responses. Emerging evidence indicates that Treg influence on immunotherapy outcomes extends beyond numerical abundance to involve a dynamic Treg-cell death axis, in which enhanced Treg survival and resistance to regulated cell death are coupled with dysfunction, exhaustion, or attrition of effector T cells. Tumor-derived chemokines, cytokines, and metabolic cues promote recruitment, stabilization, and metabolic fitness of Tregs, enabling their persistence within hypoxic and nutrient-deprived niches. Concurrently, Tregs suppress antigen-presenting cell activation, amplify checkpoint signaling, and exploit metabolic and redox adaptations including ferroptosis resistance to maintain immunosuppressive dominance under therapeutic pressure. Together, these mechanisms establish a survival-advantaged regulatory compartment that drives immune cell-fate asymmetry within the TME and limits the durability of immune checkpoint blockade. We propose the Treg-cell death axis as a unifying framework linking immune tolerance, regulated cell death, and immunotherapy resistance in lung cancer. Targeting this axis through mechanism-matched strategies that destabilize tumor-resident Tregs while preserving systemic immune homeostasis may provide new opportunities to overcome therapeutic resistance and improve clinical outcomes.