The Pokemon Company announced on Wednesday that Select Button is developing a new smartphone app titled Pokémon Sleep in collaboration with Pokémon GO developer Niantic. The project's tagline is "Pokémon Transforms Sleeping Into Entertainment." The app will launch in 2020.
The app will interact with a new "Pokémon GO Plus +" accessory, based on the original "Pokémon GO Plus" accessory for the Pokémon GO game. The device will be usable like the original "Pokémon GO Plus" during the day, and then can be used to track a player's sleeping time, which it can send via Bluetooth to the smartphone.
Source: The Pokemon Company live stream