Extracellular vesicles (EVs) are taking a central stage in intercellular communication, as conserved signaling mediators across species and kingdoms. In fact, there has been an emergence in the understanding and expansion of EVs in diverse fields including cell biology, biomedical sciences, immune regulation and vaccine development, biomarker discovery, and disease diagnosis/monitoring. To enhance and modify their form, function, and therapeutic utility, the field has expanded to modify EVs using various bioengineering strategies, which collectively have garnered significant clinical interest given their potential for drug delivery and therapeutic intervention. As heterogeneous, phospholipid membrane-enclosed structures. EVs affect the functions of other cells through their surface proteins, complex encapsulated cargo molecules (including proteins and RNAs), and select lipids and glycans. Moreover, EVs are a potential source of disease-associated biomarkers for diagnosis, composed of a molecular fingerprint of the releasing cell type (i.e., tumor-specific molecules), enabling a molecular analysis of practically all organs in the body.