The Mandalorian actress, Katee Sackhoff, said that the cast was told that the Jedi cameo from the end of season 2 was originally going to be Plo Koon. In the finale, Din Djarin (Pedro Pascal) and the baby Grogu were stuck in the bridge of the cruiser of the villainous Moff Gideon (Giancarlo Esposito) until they were rescued by Luke Skywalker. Luke's appearance was a pleasant surprise to Star Wars fans everywhere, however, as Sackhoff revealed, not everyone in the cast was given that information upfront.
When he makes his first appearance in the 1999 prequel film, Star Wars Episode 1: The Phantom Menace, Plo Koon is a member of the Jedi Council. The Jedi did not have a significant role in the prequel films other than being seen dying in the Order 66 dramatic montage, when he gets shot down by clone troopers on the orders of Emperor Palpatine. However, the 2008 series, The Clone Wars, delved deeper into the story of the character, providing fans a glimpse into his life as a respected military general, pilot, and mentor to the young padawan, Ahsoka Tano. The masked Jedi has become a fan-favorite of the pre-Empire cinematic era, but apparently, the thought of his return seemed believable enough to the stars of The Mandalorian.
Sackhoff, who played Bo-Katan in season 2 of The Mandalorian, recently sat down in a charity stream with Star Wars Explained and revealed that originally, the cast was told that Plo Koon was going to be the Jedi who saves the day in the finale instead of Luke Skywalker. Sackhoff laughed when explaining that she initially fell for it, acknowledging the unlikely scenario that the character would ever reappear considering his death seemed fairly unsurvivable. Read what Sackhoff said below:
Did you know that that's who we thought it was... That's who we thought it was, was Plo Koon. That's who we were told it was, and I'm a very gullible person.
Plo Koon's death was unfortunate for a multitude of reasons, but it really is interesting to consider a Star Wars universe where he survived his death. As we know, several Jedi managed to survive the events of Order 66 and remain safely in hiding for years following the purge. In the event of his survival, Plo could have had a significant role to play in The Mandalorian, considering his connection with Ahsoka Tano, who appeared live-action in the series with a portrayal by Rosario Dawson. Additionally, as someone with the highest rank of Jedi authority, saving Grogu would be Plo Koon's moral obligation as a previous mentor of the Force.
The events of Star Wars Episode IX: The Rise of Skywalker proved that any character could have the potential to return in some form or another, when the film decided to revive Emperor Palpatine as an empirical clone of his former self. Although incredibly unlikely, Lucasfilm always has the option to pull some strings and revive some old fan favorites in future Star Wars projects, including The Mandalorian. In the meantime, until these projects get underway, fans have some time to speculate.
Source: Star Wars Explained