Jet's skin is pretty light colored in the anime, but his English VA is the main reason people always associated Jet with being black. Also like Fadaar noted, a lot of anime productions tended to lighten up a lot of characters. It still happens. There was that commercial with an anime Naomi Osaka that did that within the past year that ended up getting pulled because people complained.
The English dub for Bebop was so damned good, I think the biggest shock for people isn't going to be how the characters look, but how they sound. The promo shots look as good as could be expected for a live action adaptation.