Pokémon Go Shiny Mew, ‘All-in-One #151’ Masterwork Research guide
Players who missed out on the Kanto Tour can now get a Shiny Mew after spending $5 and completing difficult Masterwork Research. We list out the steps.
This article references relevant content from the polygon.com website. Original article link: [https://www.polygon.com/pokemon-go-guide/23786022/shiny-mew-all-in-one-151-masterwork-research-steps-rewards]

All players who shell out $5 can now unlock Shiny Mew, via buying a pass from the Pokémon Go shop for the “All-in-One #151” Masterwork Research. You can only buy this pass until July 12 at 8 p.m. local time. This goes hand-in-hand with the “7th Anniversary Party” event.
Once you buy the pass, you’ll have an unlimited amount of time to complete the quests, which is a good thing, as Masterwork Research Tasks can take upwards of months to complete.
If you already got Shiny Mew via buying a Pokémon Go Tour Kanto pass in 2021, you cannot buy the pass again.
You can see the steps below, based on the original steps from the original set of Masterwork Research from the Kanto Tour event. We’re unable to confirm all of these steps due to the length of the tasks, but if they are different (or if they offer different rewards), we’ll update this guide. The steps below should give you an idea of the kind of tasks you will need to do to get your Shiny Mew, at the very least.
Pokémon Go ‘All-in-One #151’ Masterwork Research Tasks and rewards
Reward: 5,100 XP, 1 Premium Battle Pass, 1,510 Stardust
Reward: 5,100 XP, 3 Rare Candy, 1,510 Stardust
Reward: 1 Star Piece, 1 Lucky Egg, Shiny Mew encounter
Reward: 3 Charged TMs, 20 Mew Candy, Shiny Mew shirt