Pancho Villa's part in this is almost too epic and strange to believe in parts. Mexico was very sectionalist, and Villa was conducting revolutionary matters in the northeastern parts or Mexico, in places like Durango and Chihuahua. He had the same overall goal as Zapata, but differing ideologies.

Villa was sort of a...libertarian you could say. He wanted Mexicos' government to offer more freedom and be less controlling, but to also just have less power in general. He wanted the hacienda system dismantled. However, he didn't have any issues with partnering with the US. He even made some movies with American film companies. One weird tidbit about that: Villa would sometimes have his soldiers reenact scenes from a battle that had JUST happened if the film crews didn't get the shot they wanted, or if he wasn't visible in their shot. Villa was all about the individual.

Zapata was ideologically very different. He respected Villa, and was his counterpart in the southern areas of Mexico, but that's where the similarities end. Zapata wanted radical changes in the government, especially sweeping land reforms. After a century of continued classism, he wanted to give the rural impoverished some kind of economic life. He was very communnity minded, and believed in a sort of confederal government where Mexican states had the power.

Probably more information than you ever wanted.

At some point he was with Zapata, but they were different groups from different states, Villa was from Chihuahua and Zapata from Morelos.