Some clues have been posted regarding Dead by Daylight Chapter 21:
Some letters have been published: A, S, R, T, and a tweet that "plays" about a reference with eggs.
On August 24, the new Alien game, developed by Cold Iron Studios and published by Focus Home Interactive: Aliens Fireteam Elite, will be released.
The Alien license is one of the most requested by the Dead by Daylight community, and the developers always listen to fan requests (just see the collaboration with Silent Hill, Stranger Things and Resident Evil which were among the most requested), so it wouldn't be impossible if they were able to collaborate with the Alien license based on the universe created by the new game.
The letters could in fact be a link to the name of the game they are collaborating with: (A)lien(S) Fi(R)e(T)eam Eli(T)e, and, among other things, the letter R in the Dead by Daylight logo, is positioned right on the red, the color of fire, which is one of the words of the new Alien game.
And the tweet about the eggs could refer to the eggs that the Facehuggers contain, in the Alien movies you see a lot of them.