Brock and Misty are set to make another appearance in the 102nd episode of the Pokémon Sun and Moon anime. This special episode will officially air on December 23 in Japan. Its Japanese title is “Alola in Alola! Brock and Misty!” This episode will then air in Western territories at a later date as part of Pokémon the Series: Sun & Moon.
Source: BulbaNewsNOW @BulbaNewsNOW