So, where did that leave No One Lives Forever? Not in a good place, unfortunately. In 2013, Activision tried to explain the status of the game
in a video from community manager Dan Amrich. Amrich stated that Activision likely pawned off the rights to the IP after the Vivendi merger, and that the legal team "does not believe that we currently have the rights." As of 2020, both Activision and game designer Craig Hubbard have gone on record as stating that they have no clue who owns the rights.
By consequence, all attempts at putting out a modern release have been effectively stymied. GOG's Trevor Longino
stated in 2013 that the company "looked into it, but it's not an easy thing to do," chalking the reasons up to the licensing snag. Meanwhile,
Nightdive Studios was able to acquire the source code for the game, and began to actively pursue the license - even going so far as to trademark the games' titles in 2014. Unfortunately, Warner Bros. filed opposition to the trademark, and Nightdive's attempts at nailing down a license agreement from the company fell through.
Why? Because, as it turned out, nobody actually knows who owns the rights.
See, as of right now, it's unclear if 20th Century Fox, Activision, or Warner owns the franchise. Activision could lay claim due to the Vivendi name, Warner could lay claim on account of owning Monolith, and 20th Century Fox could lay claim due to their hand in publishing and funding it. Another twist of the proverbial knife is the fact that the legal rights to No One Lives Forever were agreed upon well before digital records were widely adopted. And given that the agreements are probably buried in a twenty-year-old file cabinet somewhere, neither Fox nor Activision were all too eager to dig through their archives.