Two independent studies published this week introduced vascularized tumor‑on‑chip platforms enabling controlled perfusion of human tumor explants with immune cells to interrogate CAR‑T function in solid tumor microenvironments. One team demonstrated the system’s ability to simulate CAR‑T infiltration and identify chemokine engineering strategies that boost activity in mesothelioma and validated findings in vivo. A Nature Biotechnology commentary framed these approaches as enabling translational screens that better predict human responses than traditional cell lines. Authors reported that the microphysiological systems allowed high‑resolution imaging, metabolomic biomarker discovery and rapid testing of combination strategies to overcome physical and metabolic TME barriers. The platforms could shorten preclinical timelines and prioritize candidates for early clinical testing, particularly for CAR‑T programs traditionally hamstrung by poor solid‑tumor penetration. Clarification: microphysiological tumor‑on‑chip systems recreate key tissue architecture and perfusion to model cell trafficking, drug delivery and immune cell interactions in a controlled microenvironment.