Tumor organoid-immune cell co-culture systems for precision oncology

Three-dimensional tumor organoids, particularly patient-derived organoids (PDOs), recapitulate key morphological, genetic, and functional features of original tumors. Co-culture with immune cells enables studies of the tumor immune microenvironment (TIME) and holds promise for personalized immunotherapy. In this review, we critically evaluate established methodologies for tumor organoid-immune cell co-culture, including reductionist, holistic (tumor slice culture and air-liquid interface), and organoid-on-a-chip approaches. We provide quantitative benchmarking of success rates, immune cell persistence, and predictive accuracy, and discuss contradictory findings, reproducibility challenges, and technical barriers that limit clinical translation. We also analyze how these systems reveal mechanisms of antitumor immunity and immune escape, and assess their applications in immune checkpoint blockade screening, adoptive cell therapy (CAR-T, CAR-NK, γδ T cells), and emerging "organoid+" technologies including spatial transcriptomics, AI-assisted imaging, and machine learning. Finally, we address ethical, regulatory, and standardization issues. Despite substantial progress, current systems face major limitations-including batch variability, loss of native heterogeneity, insufficient vascularization, and lack of systemic immune modeling-that must be overcome before clinical adoption.