A few thoughts on things that could happen in Wano right now.
1) Warlords show up.
They’re being hunted by the Marines, Wano is outside of the Marines’ jurisdiction. Seems like a no-brainer right? Especially for a cowardly Warlord like Buggy who I could easily see fleeing to Wano in a panic. It would be a very Buggyish thing for him to arrive and then be seen by Morgans and get credit for taking down Kaido and Big Mom.
Weevil could also pop up since he’s hunting down Whitebeard Pirates and Marco and Izo are on the island of Wano.
2) CP-0 gets involved.
Last we saw, they were in Wano and with Orochi now dead and Kaido in a potentially precarious position, it could be time for them to act.
3) Marines send a Buster Call.
Two Yonko, eight members of the Worst Generation, and a combined bounty of at least 18.5 billion. Marines might just decide to sink the whole damn island of Wano into the sea.
4) Blackbeard Pirates show up.
I think it’s more likely that Blackbeard is off pillaging Whole Cake Island right now, but I wouldn’t be surprised to see Moria arrive, having joined Blackbeard, to revive all the casualties of the war to strengthen Blackbeard’s crew.
5) Backup shows up for Luffy.
Luffy has made a lot of friends and Kaido has pissed off a lot of people. I could see more people showing up to help Luffy and get their licks in on Kaido. The remainder of the Whitebeard Pirates, remnants of the Roger Pirates, the Straw Hat Grand Fleet, the Sun Pirates, the Revolutionaries (you know Sabo would get his ass to Wano if he knew the situation).