As of June 2018, Pokémon GO implemented a new ffriend system. This friend system encompasses various different features, each will be detailed here.
After 2 years, trading finally enters Pokémon GO. However, you can only trade with players you're friends with and you need to be within 100 metres of the friend. When you do this, you can trade Pokémon at will. When you go into the trade system, you will see a range of CP for the Pokémon. This is due to the fact that when you trade a Pokémon, the IVs are completely rerolled. However, the higher your Friendship Level with the friend, the more likely you'll get high IVs
Trading is not a free thing, however. In order to trade, you will need to use Stardust. The requirements for stardust vary depending on Pokémon and their level.
Finally, when you complete a trade, you will gain a bonus candy of the Pokémon you sent, just as if you transferred it. If the Pokémon were caught further apart, you get more candy as well. This goes up to 3 Candy for trading over 100km. You can also achieve a medal by doing this
The Stardust Requirements are as follows
Special Trades are a type of trade that are only activated when you're trying to trade one of three things: