Seems like Kaido vs Luffy will be a fight between two guardian deities, or two beasts: The Lion vs The Dragon.
In Chinese culture, the dragon represents power, the lion strength. Their dances at the Chinese New Year are said to bring prosperity and good luck.
Wano has had a string of bad luck because it has been under the dominion of a false guardian deity, the dragon Kaido. So in order for Wano to find its good fortune, it needs the dances of the lion and dragon. In my opinion, Oda foreshadowed this fight/dance as far back as Strong World. Shiki perhaps saw himself as the lion who would challenge the dragon for supremacy, but instead was defeated by the true king of the beast, Luffy.
So how does the courageous lion defeat the powerful dragon? The dragon wields corrupted power, while the lion has strength of character, which inspires the highest kind of loyalty even among pirates, a more formidable power according to Mihawk.
*Theory by walidnusseiri / Lelouche85