Niantic has officially confirmed that from July 10th, 2019 at 1:00 p.m. PDT to July 31, 2019 at 1 p.m. PDT, players of Pokémon GO will be able challenge Armored Mewtwo in raids.

Harness the power of Armored Mewtwo!

Trainers, Mewtwo returns...with a new look. For a limited time, you can encounter this Psychic-type Pokémon in five-star raids.

Date + Time
• Armored Mewtwo will appear in five-star raids from July 10 at 1:00 p.m. PDT to July 31 at 1 p.m. PDT

Features
• For the first time in Pokémon GO, Armored Mewtwo will be available to challenge in raids for a limited time!

Avatar Items
• Do you consider yourself a Mewtwo Trainer? Show off your prowess for power and aesthetics with some stylish new items coming to the Style Shop!

Don’t miss this chance to encounter Armored Mewtwo. Are you up for the challenge?

Source: https://pokemongolive.com/en/post/armoredmewtworaids2019/

YouTube Clip - Armored Mewtwo Appears in Pokémon GO Raid Battles for a Limited Time!

Source: https://www.youtube.com/watch?v=D7nbsoa9PNk