We aren’t going to see Han Solo. That goes without saying. Harrison Ford wouldn’t do it, and you can’t recast him just for a small appearance. But Chewbacca is something else. Usually these two come as a unit, we there are plenty of times in the graphic novels where Chewie had his own missions, and given how simple it is to include someone like Chewie, it’s a definite possibility.
And the same goes with what it would be like including R2-D2. If he’s there, the assumption is that Luke is nearby, even if we don’t see him. (Which we won’t.)
If Chewie is there, even if Din Djarin just crosses his path, the assumption is that Han is nearby. Hell, maybe even the Millennium Falcon can show up. Again, this doesn’t have to be some big, elaborate interaction. Even if we just cross paths, that would be more than enough to smile and get back to business. Of course, this doesn’t come across as a fan service kind of show, it never has been, so you’d have to assume that there would be some reason to include Chewie or the Falcon or any of it.