After teasing it not too long ago, miHoYo has followed up on its announcement of a Honkai Impact 3rd x Neon Genesis Evangelion collaboration with a new trailer that you can watch below:
A fancy trailer to say the least, but very cryptic nonetheless. Little is known about the collaboration still at this point this new in-game event, but here is some information sourced from Reddit:
__V4.5 Gospel Supply (EVANGELION EQUIPMENT SUPPLY)__
Uses Gospel Supply Card (280 xtal each)
Can convert Focus to Gospel during event. After event ends, can convert Gospel to Focus
At 40 pulls, you get VD outfit (After supply ends, can be purchased with 1680 Bchips)
Longinus guaranteed at 50 pulls
__Free cards__
You can get 10 Gospel cards from 7 day login
Can get up to 6 Gospel Cards from pulling 50 times in Gospel supply
__Post v4.5 Eva equipment__
Due to copyright agreement, Evangelion equipment and outfits can only be obtained in v4.5 (still playable in later versions if you own them)
In v4.6, there will be identical gears with different names
You can mix n match eva stigs with the 4.6 stigma to activate set effects. Eg. EvaT NewstigM can activate 2pc set effect
To extrapolate from the details above, this looks to be your garden variety collaboration with special gear from the series that will be usable by the Honkai Impact 3rd cast.
It also appears that we will be getting a playable Asuka Langley and fully-fleshed out campaign too. The collaboration goes live on 25th December 2020 in the Chinese server, with no date disclosed for the rest.