The Vision and Scarlet Witch may be the first Marvel Studios series we see on Disney+ as it now has a writer and showrunner.
According to THR, Black Widow and Captain Marvel co-writer Jac Schaeffer will write the pilot and executive produce the series:
“Jac Schaeffer, one of the writers behind Marvel’s upcoming Captain Marvel movie, has been tapped to run point on the series that will focus on the two characters that are integral members of the Avengers. She will pen the pilot and executive produce, say sources.”
There are also series about Loki and Bucky/Falcon on the way, but so far neither of those have a writer that’s been announced. Since this progress is happening on The Vision and Scarlet Witch, it’s very possible that it’ll be the first Disney+ series from Marvel when the service launches.