Based on what I've read, and what's been implied with the most recent GTA V Online expansions, it's most likely going to take place in both Vice City and missio

Based on what I've read, and what's been implied with the most recent GTA V Online expansions, it's most likely going to take place in both Vice City and missions to "Cayo Perico" (their take on Colombia) for drug trafficking missions and whatnot.