Eosinophils are increasingly recognized as adaptable immune cells that exhibit diverse phenotypes and effector functions across different tissues and disease states. While they can induce pathology through degranulation and cytotoxic mediator release, eosinophils also fulfill regulatory and tissue repair roles. Advances in single-cell and spatial technologies have begun to reveal how microenvironmental cues (including cytokines, chemokines, and cell-cell interactions) shape eosinophil behavior in health and disease. These insights are critical for understanding why certain patients respond variably to therapies targeting eosinophils and related type 2 pathways. By dissecting eosinophil heterogeneity in real human tissues, researchers may identify new biomarkers, refine endotyping approaches, and develop more precise therapeutic strategies. This review summarizes emerging concepts of eosinophil biology in inflammatory conditions, highlights the impact of spatial context on eosinophil functions, and discusses the future of advanced phenotyping in guiding personalized treatments.