The line kaido gave in the top right panel seems to hint that he could be awakened. However, Oda never confirmed an awakened form for Kaido, as he did with Luffy and Lucci.
While most assume kaido simply didn't have awakening, I have another possibility. What if Kaido is an imperfect awakened zoan, like the impel down jailer beasts? And this is the reason why he never used awakening, it might have honestly made him weaker.
Now you might ask, why would Oda give kaido such a power? The answer is simple, because Oda almost never kills characters. If Pound, Kinemon, and others are any indication, Kaido is probably alive. However, Oda won't allow him to be a big threat in the future, as his time has come and gone. So what's Oda going to do? He's going to make him O-Lin 2.0.
Oda will reveal that Kaido survived because the volcano pushed him into the ocean, but that he was forced to use awakening to not drown. Awakening allowed him to breathe under water(as its a model of the fish fish fruit), but it made him retarded. Yamato will discover retard Kaido, save him, and control him(possibly with O-Tama's help) to protect Wano's borders.
Basically, the end of Kaido's story is that he turns into Yamato and O-Tama's retarded slave, protecting the country he once conquered. imo, a fitting end to his story after all he did.
