Pokémon Masters, an Android and iOS game, will have a livestream with more information this Thursday the 17th. It will take place at 10 a.m. Brasília time. The broadcast continues a series of announcements from The Pokémon Company, which recently held a press conference, a Nintendo Direct, and an E3 full of controversy.
The livestream comes at a time of considerable fan dissatisfaction thanks to Pokémon Sword & Shield. Now, with the focus back on spin-offs, The Pokémon Company presumably hopes fans will be distracted while it continues developing the Nintendo Switch games that will launch later this year.

Screenshot from the game
Pokémon Masters was previously announced at the Pokémon Press Conference 2019, and its gameplay consists of "recruiting" trainers from all the main Pokémon games to form teams and battle using their favorite Gym Leaders, Champions, and Elite Trainers from every region, from Kanto to Alola.
In some promotional images for this same livestream, what is probably the region where the game takes place can be seen in the background; it appears to be entirely original.
The livestream can be watched on the official Pokémon YouTube channel.

