i dunno, its just my opinion but i think Canelo's chin is one of the best of the past few decades. how he's never been dropped as a pro is pretty amazing to me, especially considering he's faced some big punchers. going 3 fights with GGG, 2 in his prime and taking all that is impressive.
i can see Benavidez outworking Canelo and taking a strong UD, but i just cant see Canelo getting stopped. if he does, i think it'd be a ref intervention/TKO because i dont think Benavidez has the one shot power to put Canelo down. but i think Canelo's chin might be one that lasts.