If you've been playing Pokemon GO since at least the 2nd Generation Update, you would know a few things about the Johto Pokemon found in the game. First, you would know that many of them aren't found in eggs in order for the Egg System to remain stabilized. Secondly, you would know that all the Legendary Pokemon, as well as Delibird and Smeargle, have yet to be released at this time. And lastly, you would know that Unown is no doubt the rarest to find from the 2nd Generation.
Pokemon GO players are perplexed as to why Unkown is so hard to come by - many players thought it was Region-Locked or Unreleased when the 2nd Generation was first released based upon its rarity - but many feel it has to on its mysteriousness and the role it player way back when in the Entei Movie of the Anime Series. In this movie, if you can remember, Unown was made out to be like a Legendary Pokemon in terms of their hidden power when together and how hard they were to come by.
unown is so uncommon in Pokemon GO that many players have completed their pokedex outside of it and all the Region-Locked and Unreleased Pokemon, and many of they are considering this as a completed Pokedex since Unown literally almost never spawns and it can't be found in Eggs. To this date, very few players have even seen an Unown on their in-game radar, let alone capturing one for Pokedex Purposes.
But things are starting to look up for the better! That's right, many players have seen an increased spawn rate for unown since the latest update to Pokemon GO. Unown are still very hard to come by, but a number of players have went to social media to tell of their recent discovery of Unown in their areas. Some have even caught multiple of this elusive Pokemon! Even though nothing has been said about this from the makers at Niantic, it looks promising that Unown is starting to appear far more often in Pokemon GO.