The various immune cells patrol in the body in the search for foreign substances. They follow chemotactic cues, sent by other cells, to enter adjacent or distant tissues and help resolve foreign pathogen attack. The cues are a mixture of secreted well-known bioreactive cytokines and chemokines. The recent years has demonstrated that extracellular vesicles (EVs) are also actively involved in delivering these chemokines and various other inflammatory messages between cells and tissues. This has opened up several lines of research for developing EV-mediated immunotherapeutics, diagnostics, and drug delivery in immune-mediated diseases. The excitement in the EV field has been high for a decade, but only the recent technical developments and increasingly standardizing methods to isolate and analyze EVs have accelerated the research. The complexity of this research field comes from EV heterogeneity and spatiotemporal context dependency of EV secretion; the EV-mediated cargo can e.g. support pro-inflammatory or anti-inflammatory response in the recipient cells or tissues. Additionally, several reports indicate the increase of EVs for instance in patients with autoimmune diseases, findings that are being explored for potential biomarker discovery. This chapter summarizes the current view of EVs in promoting basic processes of innate and adaptive immunity: we also discuss the inflammatory conditions such as autoimmune diseases and antitumor immune responses where EVs are reported to take part.