A CSV As A Service Dog

I'm mainly writing this just so see if what the ADA Law says about a CSV (Wolfdog) as im a bit confused if this is actually legal or not. Some places say no and yes depending on what they defind a CSV as but i thought the ADA is A federal Law so it should go above an State regulations and definitions correct? i saw a post where a wolf dog "service dog" was showing signs of extreme stress even stress biting the handler and it made me curious and the person was really entitled about me saying the law to them. i generally wanna know if im right or stupid on this. i wouldn't want a part wolf animal in the grocery store just saying...