A common misconception about Star Trek: Deep Space Nine is that the series introduced the first Black captain in the franchise. In reality, this was Captain Terrell played by Paul Winfield who sacrificed himself to save Kirk and the others. What some fans may not realize, however, is that when DS9 debuted 30 years ago, Avery Brooks' Benjamin Sisko held the rank of "Commander" not "Captain." It wasn't until much later in the series that Sisko got the fourth pip on his collar.
Source：https://www.cbr.com/star-trek-ds9-benjamin-sisko-promotion/
