Trading

Trading is an upcoming gameplay feature in Pokémon GO. It will enable trainers to trade Pokémon locally with each other.

2016
Trading has existed in the game's data as early as August 2016, where it was interpreted as an "online marketplace".

2017
In March 2017, Niantic gave more information about the upcoming mechanic. They stated that "the person needs to be in your proximity" in order for trading to occur.