The location Halstead responds to at the beginning of the episode is said to be 4400 Avers. As of April of 2021, when you go to 4400 Avers Avenue on Google Street View, Chicago Fire truck 38 and ambulance 32 can be seen responding to a call on the street corner.
Chicago's top cop was wearing military ribbons on his white uniform shirt. Most are Army, but a few are Marine Corp.