I think Kaido owns Wano Kingdom like how Big Mam owns Fishman island. Also based on the fact that Ace has been to Wano Kingdom I believe Whitebeard used to own it. But after Whitebeard died Kaido took over and now people from Wano Kingdom hate pirates. I think this will start the conflict. Kaido is probably their already working on his plans. Kaido's plans will cause the Marines to arrive as well. And that's my brief theory of Wano Kingdom<hr />Also I think before Wano Kingdom their will be a mini Sanji arc with Sanji going to the Big Mam family reunion