A recent Pokemon Go datamine may have leaked a possible connection to the upcoming Pokemon Sword & Shield games. Earlier, the popular dataminer Chrales posted a summary of his findings from a recent Pokemon Go update. While most attention was given to new items that could trigger the evolution of Eevee into new forms not currently in the game, there was also a line about "koala_settings."
Some players are speculating that this could be a reference to Pokemon Sword & Shield, as Game Freak often gives animal codenames to its Pokemon games. For reference, Pokemon: Let's Go was known as "beluga" and there are several lines of code in Pokemon Go that reference connectivity to "beluga."
Pokemon Go had great success tying into Pokemon: Let's Go this fall, and it makes sense that the Pokemon Company would want to make connectivity between Pokemon Go and other Pokemon games a permanent feature. Players can transfer Pokemon from Pokemon Go to Pokemon: Let's Go, although there's no way to transfer Pokemon from the main series game back to the mobile game.
In addition, players can unlock a "Mystery Box" in Pokemon Go when they transfer Pokemon from Pokemon Go to Pokemon: Let's Go, which allows players to catch the Mythical Pokemon Meltan for a limited time. Capturing Meltan in Pokemon Go and then transferring it to Pokemon: Let's Go is currently the only way of obtaining the Mythical Pokemon in a main series game. Players can also evolve Meltan into Melmetal and transfer it to Pokemon: Let's Go.