Star Trek: 12 Things You Missed From The Discovery Season 4 Trailer
4. Saru's Here Too
Season 3 ended with Captain Saru taking time off from Starfleet to visit his homeworld, Kaminar, and it would appear the coming season will continue his story away from the Discovery.
Saru appears in some kind of elaborate temple (possibly still on Kaminar) wearing some fancy, non-Federation duds and a brooch. The trailer later shows Saru back in uniform on the bridge of the Discovery, but the brooch remains. Has Saru become ambassador to Kaminar and that's what the emblem indicates?
Whatever his position, President Rillak states off-screen that Michael is still in command, seeming to say that Saru won't be resuming his role as captain of Discovery when he returns to active duty.