Originally Posted by
ChrisIII
Dave Filoni's twitter banner shows what appears to be concept art of Ashoka and Rex. While it could've been for "Rebels", some fans see this as perhaps a hint that Rex might show up in The Mandalorian.
Rex of course showed up in Rebels with his old friend (He and a few other Clones removed their "Order 66" chips and therefore didn't betray the Jedi), and retroactively was established as the white-bearded Rebel commando in "Return of the Jedi" (although the actor doesn't really resemble Temura Morrison that much, he's not seen up close so it kind of works.)
Temura Morrison has expressed interest in returning to SW as Rex, and certainly enough time has passed since the PT I think for Morrison to visually be a believable "middle aged" Rex (Especially if you look at pics from his recent work of Morrison bearded and/or beaded)