Anti-Combo reduce knockback while you are exposed combo.
its hypixelThis may depend on what server you're playing on, but 90% horizontal is too low for most PvP servers (Faithful, Velt, MMC, etc.).
For Chance, I suggest setting it to 100%. There really is no point for 90% chance, because a percentage that high is too insignificant to make you look legit/try to look legit. Also, chance may affect detectability on certain servers.
Anti-Combo is a feature that messes with your knockback while in a combo so that you won't be comboed as easily.