As expected, Alien: Isolation is the next free game on the Epic Games Store.
Epic's free Holiday Sale 2020 games list leaked last week, and it's all played out as accurate so far. The leak said Alien: Isolation would be today's free game and that's an affirmative, soldier.
Alien: Isolation is free to claim until from now until 4pm tomorrow, 23rd December, when if the leak continues to prove accurate, Metro 2033 goes free.