XX, not to be confused with XXX: The Return of Zander Cage, is likely named after the female sex chromosome, an indicator this anthology (in this instance a movie composed of a series of shorts) will be directed by entirely by women.
Though what I am most concerned about is if the movie will be consistently scary because anthologies are notoriously difficult to do well due to they’re only as strong as their weakest entry (one reason Rod Serling’s Twilight Zone is one of the best of the breed is that it originally aired on network television, an episode at a time. This meant that strong stories weren’t shown directly before or after weaker ones, enabling viewers to judge them each on their own merits, as opposed to being directly compared against what aired only minutes before).
And having the whole project based around the fact that the directors are women? Not too sure that that’s a great idea because I would think that it’s only relevant if their sex informs what we’re seeing on screen in identifiable ways (who we are as individuals informs everything that we do, but in this particular instance the choice of female directors need to bring some sort of additional insight–for instance, I suspect Jennifer Kent’s The Babadook would be an entirely different movie in terms of its narrative thrust as well as its priorities, if it were directed by a man) that enhance what we’re seeing on screen.
Though if nothing about the vignettes that make up XX brings the distinctiveness I spoke to earlier, then I am unsure that there’s a point.