Going to be an Andorian on the Enterprise.
Counting Spock, that's 2 whole named aliens on the Enterprise. I'm surprised they didn't add M'ress from the 70's animated series.
Now that make up and effects are up to the task there's no need for Federation crews to look as human-centric as they do.
Voyager was kind of the exception with that and even there, Kes and Neelix technically weren't Federation crew.