I think the most likely answer is either info about reviving Kuma, or help with the Smile situation.
Now that Zoro knows Kuma saved the Straw Hats twice, Zoro's moral code is going to make him want to return the favor. At the least, Zoro will want to know why Kuma did what he did.
Then, since Zoro was close to Yasuie and Toko, Zoro wanting to cure Toko to honor her father's legacy would be sweet. Zoro is also close with the people of Ebisu town, who loved Yasuie and need to be cured as well.
I feel like I'm missing something, though. Thoughts?