Space: Above and Beyond

Set in the 2050s as mankind has learned to predict and use naturally occurring wormholes for interstellar travel, they are drawn into a war with a new alien species that destroyed a colony. The show focuses on a squadron of fighter pilots in space One of them is a cloned, enhanced human used to fight in an earth bound war against synthetics and is seen as subhuman by many.

The show had a very good plot, a serialized story but also self contained episodes, interesting moral dilemmas. But it was horribly marketed by Fox so it died after a season or two. The final episode was a huge cliffhanger too.