Abstract
Potency assays for cellular immunotherapies have advanced considerably yet remain only partially aligned with the complex requirements of solid tumors, where trafficking, persistence, metabolic fitness and spatially constrained effector function are key determinants of in vivo performance. Critical quality attributes and mechanism of action can be used to anchor more informative potency strategies for tumor-infiltrating lymphocytes and CAR-engineered platforms, including CAR T, CAR-NK, CAR-M and CAR-γδ T cells. Emerging three-dimensional models, spatial biology, label-free real-time technologies and AI-enabled analytics are examined as routes to integrate microenvironmental stressors and dynamic single-cell behavior into assay design. A "plying" framework is proposed to organize potency assessment into layered, iteratively refined panels that span lean, regulatory compliant release testing through to comprehensive exploratory profiling, providing a practical path toward clinically relevant and regulatorily acceptable potency assurance for solid tumor immunotherapy products.