It's a bit older, probably 90s or so. It is about aliens who have visited Earth, officially, and there is a lot of political theme around that IIRC. So it's not Alien Nation where it has a cop show focus. One tiny element I remember that might help to determine which one I am thinking of: Two humanoid alien main characters dealing with government politics on Earth and typically conversing with each other: one is the more aggressive, mistrusting type, the other one is more diplomatic and peaceful, and that one has a habit of making distinct, graceful/artful gestures with his hands while talking. The show might have had Steven Spielberg involvement, but I don't remember clearly.