No 1 Reason Kaido will not die.
Straw Hats have never killed anyone on screen and it will not happen now neither. Zoro hasnt a confirmed kill on panel , it has literally never happened. There is a moral standard to the straw hat pirates which includes no killing.
No 2 Reason he will not die
If he dies he gets his dream ending like Roger and WB, which is exactly the reason it will not happen at all. He doesn't deserve such an ending. Luffy destroys his opponents dreams there is no death included there ever.
No 3 Reason he will not die
Odas formula always goes with Luffy beating the main villain in the end, Zoro the second strongest, Sanji the third strongest etc.Even after writing the rooftop chapters , Oda still decided that we are going back to the standard formula.
Why No 1 Reason is wrong - Both Zoro and Robin have killed in Manga Panels, during Zoro's introduction in the manga it is stated that Zoro actually killed Helmeppo's Dog (on screen with a panel) and off screen with the Baroque Works stuff. Robin has also killed many fodder on screen using clutch techniques to break people's spines and necks, also she was an assassin before Alabasta for many years.
Why No 2 Reason is wrong - Kaido's dream is not to just die, but to get a glorious death, he wants a huge death, there is a WRONG way to die in his mind. He says how Oden, Whitebeard and Roger all did it right, he also seems to imply that Rocks died in the wrong way, being completely forgotten and not accomplishing anything with his death. Sounds like anyone? If Kaido dies as a Dragon by Zoro in Wano, most people in the outside world will never know, there will be a legend about a Dragon dying and that's it. he won't accomplish shit and he would be forgotten.
Why No 3 Reason is wrong - There are many arcs where Luffy doesn't beat the main villain: Sabaody, Impel Down, Marineford, Whole Cake
and there's also two arcs in which Zoro, of all people, gets to defeat the Villain for the rest of the arc or at least before Luffy does: Shells Town (Captain Morgan) and Fishman Island (Hody Jones), which Zoro defeats him even underwater.
Just read my ZKK theory on my signature and you know there's a chance it will happen.