Stan Lee’s role(s) in the Marvel Cinematic Universe took an interesting turn during Guardians of the Galaxy Vol. 2. Lee was shown in space, speaking with cosmic characters The Watchers. In the brief scene, Stan Lee made reference to multiple past cameos, not so subtly implying that he’s actually been playing one character the whole time. Unfortunately, it looks like that plot point will likely not reach its fruition, as Lee died before he could record an appearance in the upcoming Guardians threequel.
Article source: https://www.cinemablend.com/news/2471753/the-russo-brothers-share-set-photo-from-stan-lees-final-cameo