The developer behind Pro Skater 1 + 2 has been merged into Activision Blizzard however.
Tony Hawk's Pro Skater 1 + 2 was released a year ago and got a somewhat mixed reaction, but mostly positive reviews. During Christmas, all Activision's accounts in social media have been sending Christmas wishes to all their fans, including the one from the Tony Hawk series on Twitter.
But eagle eyed fans have noted something really interesting with them, as they include "12 < 312" in the digital Christmas cards (check in the lower left corner of the billboard in the image below), something they also did for Halloween, so this is now a repeating pattern and no random thing. Exactly what this means is up for speculation, but a new Tony Hawk game would make sense for Activision as EA is working on Skate 4.
It should be noted though, that the Tony Hawk's Pro Skater 1 + 2 developer Vicarious Visions has been merged into Activision Blizzard. If some from the team has started a new skateboard team or if it's a brand new developer doing a potential new Tony Hawk remains to be seen.