Two seminal papers in Nature journals report microengineered tumor‑on‑chip systems that vascularize human tumor explants and permit controlled perfusion with immune cells to model CAR‑T cell activity in solid malignancies. The platforms retained native tumor architecture, enabled live imaging of CAR‑T infiltration and allowed testing of chemokine‑directed engineering strategies and pharmacologic modifiers to improve CAR‑T efficacy. Authors validated findings in matching in vivo models and identified metabolic and biomarker correlates predictive of response. The technology provides a preclinical bridge to better predict cell‑therapy performance in solid tumors and offers a rapid, human‑tissue screening tool for candidate combination strategies and safety assessments.