The official Pocket Monsters anime Twitter account has revealed details on the new show's opening theme. Translations follow:

Believe it or not, the opening theme for the new series
will be sung by After the Rain (Soraru x Mafumafu),
with Mafumafu handling the production, lyrics, composition and arrangement.
Please wait for a follow-up report for further information.



Source: https://twitter.com/anipoke_PR/status/1184793679409451011