Ahsoka Tano is one of the few characters alive at the time of The Mandalorian that would still be wielding a lightsaber. When we last encountered the former Padawan of Anakin Skywalker, she was recruiting Sabine Wren to go on a mission to the Outer Rim to search for their friend Ezra Bridger.
It is very possible that in that journey they come across the path of the Mandalorian and maybe during that encounter they are ambushed by Moff Gideon, his Darksaber, and a small legion of still loyal to the Empire Stormtroopers.
If it was Ahsoka who engaged in epic lightsaber action with Moff Gideon, would one think it would be a pretty quick contest. Ahsoka is a gifted fighter who excels at using two lightsabers at once. She would make quick work of the Moff and surely cut him down quickly giving the Darksaber back to Sabine Wren or possibly Mando himself.
Though the battle would be short, it doesn’t mean it wouldn’t still be epic. The duel between Maul and Obi-Wan on Tattoine was brief, but also epic in it’s scope and meaning to the characters and the overall story of Star Wars. Moff Gideon could get destroyed in epic fashion with first Ahsoka slicing her way through his legion of Stormtroopers before taking him out.