Peter Parker's origin has always been tied to "with great power comes great responsibility", which itself stems from the passing of Uncle Ben. You might not have noticed it, but he even made it into Homecoming.
Granted, it was quite subtle, but it was there. Writer John Francis Daley recently spoke to EW about Uncle Ben, confirming his existence in the MCU and Homecoming's world. At one point Peter says "all that she's gone through", referring to Aunt May. Daley confirms that was in reference to Uncle Ben.
Daley also reveals there was a larger moment for Uncle Ben in earlier drafts.
"We did talk about there being a scene where [May] references him directly," Daley says. "It was when [Peter] was getting ready for homecoming and the wardrobe she was giving Peter was all Uncle Ben's clothes. It was a nice moment, but we also knew that it veered away from his arc. If you're going to talk about someone's death, you don't want it to be a throwaway."
While Uncle Ben is an important part of the Spider-Man mythos, it's probably for the best that he didn't get more screen time in this version. People have seen Spider-Man's origins twice now on the big screen, and no one wanted a third go round. References it this way allows the film to get the character moments from it without rehashing it.
You can find the description for Spider-Man: Homecoming below.
A young Peter Parker/Spider-Man (Tom Holland), who made his sensational debut in Captain America: Civil War, begins to navigate his newfound identity as the web-slinging super hero in Spider-Man: Homecoming. Thrilled by his experience with the Avengers, Peter returns home, where he lives with his Aunt May (Marisa Tomei), under the watchful eye of his new mentor Tony Stark (Robert Downey, Jr.). Peter tries to fall back into his normal daily routine – distracted by thoughts of proving himself to be more than just your friendly neighborhood Spider-Man – but when the Vulture (Michael Keaton) emerges as a new villain, everything that Peter holds most important will be threatened.
The cast includes Tom Holland, Michael Keaton, Zendaya, Donald Glover, Jacob Batalon, Laura Harrier, Tony Revolori, Tyne Daly, Bokeem Woodbine, with Marisa Tomei, and Robert Downey Jr. It also includes Jon Favreau, Martin Starr, Kenneth Choi, Michael Mando, Selenis Leyva, Isabella Amara, Jorge Lendeborg, Jr., JJ Totah, and Hannibal Buress.
Guardians of the Galaxy Vol. 2 and Spider-Man: Homecoming are in theaters now, followed by Thor: Ragnarok on November 3, 2017. After that Black Panther debuts on February 16, 2018, while Avengers: Infinity War hits theaters on May 4, 2018. Ant-Man and the Wasp is slated for July 6, 2018, followed by Captain Marvel on March 8, 2019.