Short answer--the keyart for the house seems to reflect the "Eras" of the Trilogy that has been made. After Hours with the red suit + glasses, DawnFM with the Old Man Abel, and the new album (or as they are dubbing it, the "terrifying new tale") with the crackled skull. Murdy has also acknowledged that only music from the trilogy will be represented (which technically makes this the first....kind of Preview House, since Horrors of Blumhouse 2018).How do we know it's part of the Nightmare Trilogy? While the timing makes sense, I just don't see anything anywhere stating that. I figured it may be possible the end of the trilogy is its own thing and this could just be a nice cross promotion.
Long answer probably warrants a better deep-dive within the Weeknd thread respectively, as all of the preview videos for the upcoming album (excluding the Sao Paulo video that got posted today) are CG trailers with thematic elements connecting all of Weeknd's work into the coming project.