https://techcrunch.com/2018/08/16/pokemon-go-is-getting-a-big-new-special-research-quest-next-week/

Just a few months back, Niantic added its first “Special Research” to Pokémon GO. Sort of like an in-game quest, the research had players complete a series of tasks (often over a number of days) to unlock an otherwise unobtainable Pokémon.

Now they’re back with another one.