Today, Niantic announced that Lucky Pokémon will soon be introduced to Pokémon GO to coincide with the recently released Friends and Trading features.
When traded, Pokémon will have the chance to become sparkly Lucky Pokemon, requiring less Stardust to power up. The longer a Pokémon spends inside a Trainer’s storage prior to the trade, the higher the chance of them becoming Lucky Pokémon once Traded with a Friend.
Gifts also can include special new surprises. Trainers who send Gifts to friends will now receive XP for doing so and Gifts also have a chance of containing Stardust!
The official Pokémon GO Twitter account clarified that Lucky Pokémon are not yet available. After Pokémon GO has been updated for all users, this feature will be enabled.
Update 7/25: Lucky Pokémon are now available.