Spider-Man: Far From Home director Jon Watts leaves the door open for Uncle Ben to appear in a future MCU movie. Both Tobey Maguire's and Andrew Garfield's iterations of Your Friendly Neighborhood directly dealt with the passing of Uncle Ben, a vital moment in Peter Parker's life that set him on the path of being a hero. By the time Sony and Marvel Studios struck a deal to allow Spider-Man be a part of the MCU, general audiences were overtly familiar with Spider-Man's origin. Hence, when Tom Holland's version was introduced in Captain America: Civil War, Peter was already established as a crime-fighter in New York.
Though Uncle Ben hasn't appeared onscreen in the MCU, there have been multiple allusions to him, and Far From Home even sports a clever reference (the suitcase Peter packs for the European school trip). In many ways, Tony Stark essentially assumed the mantle of Uncle Ben for Peter, but some are still wondering if Ben will show up at some point. According to Watts, everything is on the table for the time being.
In an interview with Screen Crush, Watts addressed the topic of Uncle Ben in the MCU. He confirmed that Ben exists in the franchise (see: the aforementioned suitcase Easter egg) and went on to add something very interesting:
“Yeah. I mean, we don’t know. We never specifically say anything about him. So whether or not he’s around or not... Yeah. Everything’s on the table, is how I like to say it.”
These comments seem to imply that it's possible Uncle Ben could still be alive in the MCU, but the odds of that actually being the case are low. It's been heavily implied Ben's tragic death did occur offscreen; Civil War includes a line where Peter seems to be regretfully recalling the incident ("When you can do the things that I can, but you don't, and then the bad things happen? They happen because of you.") and in Homecoming Peter mentions how he doesn't want Aunt May to know he's Spider-Man because she's already been through a lot and he doesn't want to add further stress to her life. While not explicitly saying Uncle Ben is dead, those two instances strongly suggest it happened. The filmmakers just trust audiences to know what they're talking about since Spider-Man's origin got two different movies in a 10-year period.
If Uncle Ben ever does show up in the MCU, it'll probably be via flashback or dream sequence. At the same time, it's worth wondering if the opportunity to include Uncle Ben has passed. Considering how Far From Home ended, Watts and company have bigger fish to fry in the MCU's Spider-Man 3 than trying to work Uncle Ben in somehow. It would be great if they found a way, of course, but it would have to be a natural fit for the story. Time will tell, but Marvel will consider all options as they work away on figuring out what's next.
Source: Screen Crush