There has been no official announcement for this event yet, but the developers of the shooter Goddess of Victory: NIKKE are preparing a collaboration with the popular anime Evangelion. As part of this event, players will get access to three characters from the well-known title about big robots, girls in tight suits, and one of the most vile protagonists in human history. In particular, we are talking about Asuka, Ray, and Mari, who will be playable as part of the event and will remain with players forever.
You can also take a look at the characters and their skins, but this is a leak, so the images are covered in self-promotion from the source.
The timing of the collaboration remains unknown, so all we can do is wait.