Since Stan Lee’s ing, the MCU has been without his beloved cameo appearances, Ryan Reynolds’ Avengers: Endgame. Since then, all subsequent MCU films have not featured him as a cameo.
Deadpool starring the titular Ryan Reynolds' as the Merc with a Mouth spent time in production limbo for years before leaked footage in 2014 showed studios that audiences wanted to see the film made. Reynolds' portrayal of Wade Wilson in 2009's Deadpool 3 is confirmed as an MCU film in the future. Not much is known about the film besides Reynolds' reprising his role, but it will be a wild ride if the previous two films are any clue.
Now that Ryan Reynolds' The Princess Bride than in the first cut of the film.
With the MCU now exploring the Multiverse, Doctor Strange in the Multiverse of Madness these characters are starting to appear in the MCU. Now that this is happening, the timing is right for someone to take up the cameo legacy that Stan Lee left behind. Deadpool could first start showing up in cameos before Deadpool 3, and his ability to break the 4th-wall would be the perfect medium to introduce himself and other characters from different franchises. Who else besides Deadpool would know why a character from a different universe is suddenly here?
Deadpool appearing as the cameo appearance in MCU films would also reflect how he frequently shows up in many different characters' stories in the comics. He is uniquely connected to many characters through various multiverse continuities in the comics would allow a more comic-accurate depiction of the character. This could easily be reflected in the MCU with Deadpool appearing as the cameo in future films.
With Ryan Reynolds' Deadpool 3 in development, now is the ideal time for him to replace Stan Lee as the cameo appearances in the MCU. He could easily appear in various MCU projects due to multiple factors linked to his 4th-wall breaking shenanigans and connections to many characters. If there's anyone capable of filling the cameo void left by Stan Lee, it's Ryan Reynolds' Deadpool.
