Unfortunately, "Pokemon GO's" developer Niantic has been mum over any news, plans or details in regards to "Pokemon GO" trainers being able to use their Pokemon to battle one another. However, there is already a third party app that could solve this issue for "Pokemon GO" fans.
Storimod allows "Pokemon GO" players to battle one another in real time, at least not in the actual "Pokemon GO" game though. It is stated on their official website as "we have Battlemõd, the unofficial first real-time PvP engine for Pokémon Go. It is in it's very beginning phases, but easily provides hours of nostalgic fun after you get done hunting in the real world."
The rest of the features are nice, the app is simple and fast, not really pretty, but does the job well. You can watch a video overview of the app here:
To set your expectations right, it's actually far from fighting "Pokemon GO" gyms. What it does is it takes the information of your Pokemon from your "Pokemon GO" Pokedex and uses that information to battle it out. Pokemon GO Hub reviewed Storimod and this is what they had to say about the third party "Pokemon GO" app "There are no animations at the moment, but it's still a lot of fun, as it's actually real time and the other trainer is a flesh and blood opponent!"
Storimod is also safe to play you don't need to worry of your "Pokemon GO" account getting banned. This third party "Pokemon GO" app is now available on Android and coming soon on iOS.