Multicellular ecosystems: Linking cellular diversity to tissue function and disease.
Tissue function emerges from coordinated interactions among diverse cell populations, whereas disruption of these interactions can lead to dysfunction. Recent advances in single-cell and spatial genomics have not only cataloged cellular diversity but also revealed how tissues are organized as dynamic multicellular ecosystems. Moving beyond descriptive cell atlases toward functional, system-level representations represents a major frontier in tissue biology. In this review, we outline conceptual and methodological frameworks for dissecting multicellular coordination, highlight recurrent multicellular ecosystems across physiological and pathological contexts, and explore translational opportunities such as patient stratification, therapeutic reprogramming, and regenerative strategies. Viewing tissues through an ecosystem lens provides a unifying framework that links cellular diversity to emergent tissue function and informs strategies for disease intervention.