During Nintendo's Japanese Indie World presentation, the Cadence of Hyrule release date for Nintendo Switch has been announced as June 2019.
Fans have speculated the precise release date will be June 20th, based on inspecting source code on Nintendo's website. But this may just be used a placeholder date as it coincides with the end of Spring, which was the original release date provided.
It is not uncommon for Nintendo Switch games to be available immediately following their coverage during Nintendo's presentation at the annual E3 event. With this event running in June, keep an eye out for more Cadence of Hyrule coverage and announcements.