It's possible there will be a cameo from Rosario Dawon's Ahsoka Tano in The Mandalorian season 3. Anakin Skywalker's former Padawan during the Clone Wars, Ahsoka Tano was originally voiced by Ashley Eckstein. The character made her live-action debut in The Mandalorian season 2, before returning in The Book of Boba Fett. The character is soon due to star in her own live-action Disney+ TV show, set during the same period, between five and eight years after the events of Return of the Jedi.
All the evidence suggests Ahsoka Tano is on a mission to locate a missing Imperial leader, Grand Admiral Thrawn. He vanished into the Unknown Regions years ago, before the outbreak of the Galactic Civil War, along with Ahsoka's good friend Ezra Bridger. This makes Ahsoka's TV show particularly important, given it is generally assumed Thrawn will be the main villain of the Mandoverse shows. Naturally, there's intense speculation Ahsoka Tano could appear in The Mandalorian season 3.
Rosario Dawson Filmed Ahsoka After Production Wrapped On The Mandalorian Season 3
Production on The Mandalorian season 3 began in October 2021, and wrapped in March 2022. Production on Ahsoka began two months later. Both shows shot in Los Angeles, so there's no reason Rosario Dawson couldn't have been present for both. There were even reshoots for The Mandalorian in early July, and it is easy to imagine Dawson fitting these into her schedule. In the latter case, though, it is likely she would only make a brief cameo.
It's Unlikely Ahsoka Will Appear In The Mandalorian Season 3
Ultimately, though, it appears unlikely Ahsoka Tano will appear in The Mandalorian season 3. While it is true Ahsoka has past connections to Mandalorian leader Bo-Katan Kryze, the plot of season 3 seems to be focused on Mandalorian culture and heritage, and a Jedi would not fit with this narrative. It's hard to see why Ahsoka Tano would fit into The Mandalorian season 3's plot, other than to make a token cameo for the sake of it.
The production schedules roughly align, which is a positive sign, but Ahsoka is likely to still be on her quest for Thrawn and Ezra. This likely means she'll even be out of contact, far from Mandalore, and there's no realistic reason she should head to other worlds confirmed to appear in The Mandalorian season 3 - Nevarro, Tatooine, or even the former galactic capital of Coruscant. It seems logical to assume Ahsoka Tano is not in The Mandalorian season 3.