Precision cytokine modulation to overcome tumor microenvironment-driven resistance to immune checkpoint blockade
Xiaodong Wang, Junjie Wang, Qianqian Wang, Gouping Ding, Yiping Huang, Yeqian Feng
Abstract
Immune checkpoint inhibitors (ICIs) can elicit durable remissions, yet most solid tumors show primary non-response or acquired resistance because the tumor microenvironment (TME) limits T-cell priming, trafficking and effector fitness. Cytokines orchestrate these barriers by shaping spatial immune architecture, regulating suppressive myeloid programmes and inducing inhibitory ligands such as PD-L1. In this Review, we synthesize mechanistic and clinical evidence and propose a push-pull framework for cytokine modulation during checkpoint blockade: locally amplifying Th1/CTL-supporting signals (IL-2/IL-12/IL-15 and type I/II interferons) while selectively attenuating dominant suppressive circuits (TGF-β, IL-6/STAT3, IL-8-CXCR1/2, IL-10 and TNF-driven exhaustion). We critically contrast successful and failed cytokine-ICI combinations, highlighting how systemic exposure, network redundancy and counter-regulatory feedback have constrained several engineered agonists and explain why certain blockade strategies can improve efficacy while reducing immune-related toxicity. We discuss next-generation solutions-tumor-activated pro-cytokines, intratumoral gene delivery and immunocytokines-that concentrate activity within resistant niches and widen the therapeutic window. Finally, we outline actionable biomarkers, including transcriptomic signatures, plasma cytokine kinetics, myeloid/neutrophil metrics and spatial TME profiling, to stratify patients and guide dosing, sequencing and adaptive add-on strategies. Rational, biomarker-guided cytokine modulation offers a path to convert immune-excluded tumors into durable ICI responders.