It's still a bit broken when you click on it, since it'll lead to nothing. However if you hover over it, there's already Star Guardians, K/DA and Odyssey from the past events, and even Galaxy Slayer Zed now has his own bio and blood type in Odyssey.
(I found this out by looking reading the wiki and looked at the Odyssey skin tab, and seeing Zed had his own bio and other trivia for him).
I'm guessing that they're gonna add Event Horizon with the upcoming Dark Star skins? But I'm excited that the universe is adding that tab for it.