Well, it seems that might be the case! In an appearance on Mythical Kitchen earlier today, Tony Hawk spilled the beans about "something" that he's working on with Activision right now, although he wasn't willing to divulge too much:
"I wish I could tell you more, but I can tell you that I've been talking to Activision again, which is insanely exciting. We're working on something. That's the first time I've said that publicly. It will be something the fans will truly appreciate."
As you can probably tell, Tony seems extremely hyped for whatever he's cooking up with the folks at Activision, and we're obviously hoping it's a new game - maybe that THPS 3+4 remake that was supposed to happen years ago?
Whatever it ends up being, it's exciting to know that we've potentially got more Tony Hawk's Pro Skater on the horizon, and don't forget that Activision is part of Xbox these days, so technically a new game would be an Xbox first-party title!