The Mandalorian Season 2 shook the world with the appearance of Luke Skywalker at the ending of the final episode. Even considering that Mark Hamill aged fine, he cannot play the role of Young Luke without the help of CGI and special effects.
Fans were eager with the return of Luke and had been calling to cast an actor with an uncanny resemblance to young Mark Hamill as if he was his son, even Mark Hamill was thrilled with the idea and pitched it himself, it is The Falcon and The Winter Soldier's Sebastian Stan. With no word yet that Sebastian Stan would be playing Luke Skywalker in the third season of The Mandalorian, it would be a delight to the fans if he will.
Sebastian Stan, who will be reprising his as The Winter Soldier in an upcoming Disney+ series The Falcon and The Winter Soldier, expressed his interest in filling up the shoes of the legendary Jedi Master in 2017. Mark Hamill even joked about it and tweeted "Sorry to disappoint you but I refuse to say ‘Sebastian Stan – I AM YOUR FATHER!' (Even though, in fact, I am.)" Fans were exhilarated to see this and since then called to cast Stan as Young Luke. Recently, a deepfake video went viral comparing the resemblance of the two actors.
Considering that Stan is already with Disney, it would be easier for him to get cast in another Disney project. With his projects already done filming, Stan is free to take up future roles and fans are hopeful for him to be Young Luke Skywalker.
Aside from The Mandalorian 3, another opportunity where Stan can enter the Star Wars universe is through Rogue Squadron with director Patty Jenkins. To introduce Stan as Luke Skywalker in a Star Wars theater release would make more sense as the character that he would play is too iconic to be a recast in a series, more so a role too big to be a cameo, with Luke being the founder of the Rogue Squadron.
The Mandalorian 3 will be released in December 2021 on Disney+.