How does one get the black skins?

What are the Champion unlock challeges? I would like to use them, but don’t know how.

it says i’ve completed the missions to get the champion skins but their still locked for some readon i wanna usee them cause their are super sick lookin

i have a similar problem. i got all of the unlock challenges on 100% but only got 11 skins after the first match i played.

it happens. Happened to me for a few mastery skins after they changed the requirements. Just wait a few days, or submit a support ticket.

I just did the Mikey dlc 5 times and got multiple skins each run.
Have black skins now for most of the characters.
Not sure if it made a diff but I matched the play character with the challenge.
1 Beatrix 3 Alani and 1 Galilea.

Hey yal, just remembered,
YOU MUST PLAY THE LEVEL TO UNLOCK AND JUST START IT. AND THEN IT WILL BE GIVEN, LEAVE OR NOT