This concept sketch, which I did as a little personal diversion, depicts a fictional subspecies of American bison (Bison bison peténesis, named after the Petén region of Guatemala) that would have adapted to live in the tropical forests of Central and South America. If they ever existed, they’d probably travel in smaller and more tightly knit herds than their prairie-roaming brethren, and they would eat more leaves and shoots since those are more common in jungles than grasses.
In reality, there actually is a population of plains bison (B. b. bison) native to northern Mexico. It’s possible the Aztecs kept some of these at their menagerie in Tenochtitlan (the Spanish identified them as “Mexican bulls”), but they would have represented exotic imports like lions at your local zoo.
By the way, if you wonder what the adjective “Neotropical” means, it refers to the tropical regions of the Americas (aka the “New World”).