It's being rumored that She-Hulk and Jen Walters, the cousin of Bruce Banner, will make her MCU debut in Spider-Man 3.
TVO, from the Lord of the Long Box YouTube channel, offers insiders have filled him in that Jen Walters, aka She-Hulk, will be the lawyer for Spider-Man.
Spoiler alert: The mid-credit scene for Far From Home showed Mysterio revealing that he was not only "murdered" by Spider-Man, but Mysterio also revealed Peter Parker's identity. It's then insinuated by J.Jonah Jameson that Spider-Man is now a wanted criminal.
She-Hulk coming to the MCU with Spider-Man 3
TVO says there was a rumor going around that Matt Murdock, aka Daredevil, was supposed to be Spidey's lawyer, but the problem is that Daredevil can't come into the MCU for another 18 months or so. Since Marvel has already started on the script for Spider-Man 3, they can't even contractually use Daredevil or Matt Murdock because of the Netflix deal (info on Daredevil reboot here). So "scratch Daredevil," and She-Hulk is going to be used.
The YouTuber goes on to say that he doesn't know if Jen Walters will be hulked-out in Spider-Man 3 or just remain in the human form, but the plan is to use her as Spider-Man's lawyer and that she will eventually become She-Hulk.
In the comics, following an accident, Bruce Banner gives his cousin a blood transfusion filled with his gamma-irradiated blood, which enables Jen Walters to transform into She-Hulk at will. Perhaps Spider-Man 3 sees Jen Walters get hurt in an accident involving a Spider-Man fight, with Mark Ruffalo's Bruce Banner coming in for the save.
Worth a mention is that ABC recently passed on an all-female Marvel TV show this past January, which could have featured She-Hulk.