January 2023
This is a recolor, as shown there you can buy it with either Apex Coins or Legend Tokens.
If you want to buy the recolor with Legend Tokens, you'll have to own the original skin, which is in this case the "Sixth Sense" skin for Caustic.
Though, if you don't own this skin, you won't be able to purchase it with Legend Tokens.
So you can buy it with Apex Coins, or if you want to use your Legend Tokens, you'll have to buy the original skin.