You can use this to your advantage by waiting for him to use his Q and W, then fight him. Aatrox is a very cooldown dependent champion and from my experience, most Aatrox players spam their abilities on cooldown pretty much. To avoid his W, try to stand behind minions, it is hard to dodge if you are out in the open (similar to something like Illaoi E). His Q can be really annoying and his W is hard to avoid as Sion because you have very little mobility.
His passive is really strong against you (doing max health bonus damage on his first auto attack). Aatrox is one of those matchups that is heavily reliant on skill and how strong Aatrox is in the meta.
