Beloved characters Hailey Upton, Sylvie Brett, and Blake Gallo are leaving One Chicago, which has left fans wondering why. Showrunner Andrea Newman explains that after 12 years, it's natural for things to change and new dynamics to be introduced. Similarly, Chicago Med showrunner Andrew Schneider agrees that bringing in new characters keeps the shows fresh. Despite the departures, Newman is confident that Chicago Fire will continue to be strong. Gallo moved to Michigan, Brett moved to Portland, and Upton's departure is yet to be announced. However, fans can still enjoy the action-packed One Chicago shows.