Let me just unpack the revelations that come from this.
Jhin is in Piltover, or Camille is in Ionia and has taken a large amount of guards/ police with her. Jhin has for some reason allowed Camille to find him, or has been unable to shake her and set up for a final showdown. Either he was unprepared and loses easily, which I seriously doubt (it would break my suspension of disbelief that this legendary serial killer would go down so easy), or we haven't seen the end of the battle and he has another trick up his sleeve.
Ionia has once again been invaded by Noxus. Yasuo has been redeemed after the events of Confessions of a Broken Blade and fights with Irelia. Given what we know, nothing else seems out of place among the Ionians. Noxus has decided to deploy Sion. Hopefully Swain is a little more strategic than Darkwill, but this battle doesn't say much about that.
Riven has likely been captured in the Ionian Invasion 2 and shipped to Noxus. She is then forced to fight in the arena. We don't know why, but presumably the fight between her and Draven is to the death. One of them is probably going to die. I don't know how Riven gets out of this situation unless she was promised freedom if she won, but I don't know if that's how Noxus works. Noxus might offer her a place in the army, but freedom? Seems unlikely to me.