The latest news on this front comes from a really interesting article at Ballot Access News written by the widely-respected election expert and advocate for third party/independent ballot access Richard Winger.
According to this story, U.S. Senator Kamala Harris had been set for an interview with leaders of the Working Families Party, but at the last minute she decided not to attend. The story says that other Democrats running for President had already had similar interviews with the WFP, including Bernie Sanders, Elizabeth Warren, Cory Booker, Julian Castro, and Bill de Blasio.
The Working Families Party will eventually endorse someone for the 2020 Democratic presidential nomination.
See full story here.