A new game based on The X-Files is in the works, according to series creator Chris Carter. All we know is that it will be a "narrative" game (which could mean anything, really)—he slipped the news into an interview about the end of series 11 of the TV show, and wasn't pressed on it further. No doubt we'll find out more soon.
"I made a joke the other day about The X-Files, the musical, but in reality, they’re actually making a really interesting narrative video game, different from the one that’s been launched already," he said in the interview with X-Files News.
I presume the already-launched game he's referring to is The X-Files: Deep State, a hidden object game that released on mobiles last month (to generally poor reviews). It's been a full 20 years since we had a proper X-Files game on PC—Richard returned to it in 2013 and found it to be "surprisingly okay". Read his take here.