Even before the MCU started, Stan Lee has always been making cameos in films from Spider-Man to the X-Men. With Lee passing last year, a lot of people were wondering when his final cameo will be, and director Joe Russo seems to confirm that it will be in Avengers: Endgame.
He said this during a Marvel press event in India:
"I believe that his final cameo is in Endgame. I don't remember if he was well enough to do the Homecoming [means Far From Home] cameo or not."
Not too far back, it was said that Lee's final cameo would be in Spider-Man: Far from Home, but seeing that the Russos have a huge hand at ending a huge chapter for the MCU, it would make sense that Russo would know about Lee's last appearance.
If it's any consolation, it looks like Russo doesn't know too much about what will take place in Spider-Man: Far from Home, so it's likely that he won't know about a cameo at all. Seeing that Spider-Man is considered to be Stan Lee's favorite among his creations, it would make sense that his last appearance would be in a Spidey movie.
Then again, Lee has said before that he would have loved to appear in more cameos. It's not entirely impossible that Marvel Studios has already had a digital scan of Lee in their archives so they can just keep putting him in movies as per his wishes. But a great sendoff to him would be greatly appreciated as well.
Catch Stan Lee one more time in Avengers: Endgame which comes out April 26.
See Also: Avengers: Endgame Theory Says Captain America Won't Be Sacrificing Himself In The Film