It's only one episode, the first episode, but for now only one. And they have hired a black director before for season 1.
George Tillman, jr. -
http://www.imdb.com/name/nm0863387/?ref_=ttfc_fc_dr12
You might see more this season. The RZA directed an episode of Ironfist. Could see more of both of those guys.
I don't want to look too much into this, because they do hire a diverse group
of directors for their shows from black, white, asian, latino and a few women have directed some episodes in the Netflix Marvel Universe.