Most documentaries these days don't get a "wide" release (unless you're Dinesh D'Souza or Al Gore) so most likely it will show up on the streaming services. I doubt it will see a theatrical release, except maybe in big cities for Oscar consideration.
DVD/Blu-ray is a question mark. I think some titles are bypassing physical release these days which is kind of sad. It's like these movies never exist.
Here is part of an e-mail from John Scheinfeld, Producer/Director of the Sergio DOC (he also has done the forthcoming Herb DOC):
SERGIO MENDES: IN THE KEY OF JOY had its world premiere screening on January 18, 2020 at the Santa Barbara International Film Festival. The screening was in the sold-out Lobero Theatre, the second biggest venue at the festival (600+). You could feel the electricity in the house when Sergio took his seat. The audience was with us right from the start, reacting and laughing in all the right places, even applauding after performances in several music clips. We got two standing ovations – one for the film and another following Sergio’s 3-song live set with his band after the Q&A (actually, the crowd got to the feet for the first song and never sat down). It was, truly, a special event. Here’s a link to the review:
There was a second screening in a 250-seat theatre the next day which was also sold out. On February 11, 2020 there was a private screening at the Skirball Cultural Center in Los Angeles for friends, colleagues and family of Sergio and Gracinha in honor of his 79th birthday A final screening was open to the public at the Grammy Museum in Los Angeles on March 11th. The film was supposed to open theatrically in May of 2020, but with COVID-19, it has been postponed. There are so many unknowns at the moment, so we’re not yet sure when and on what platform the film will be released.