User blog comment:Kaido King of the Beasts/Chapter 813: Up in Vinsmoke/@comment-5398287-20160121132556/@comment-24769684-20160121151641

There's no evidence to suggest Jack will return. If anything, Luffy will carry Jack's atrocities in his memory for a future battle, because honestly, I don't think he's at Jack's level yet.

But yeah, there are still loose ends on Zou to be tied up, most prominently Raizo. Given Luffy and Zoro's apathy to Sanji's note, a rescue doesn't seem incredibly imminent.