In the real world, no. They were not introduced until The Next Generation. In the Star Trek universe, maybe.
Cardassians are a spacefaring race in the fictional Star Trek universe. The Cardassian Union was introduced in the Star Trek: The Next Generation episode "The Wounded". However, the Federation already knew of them in The Wounded, and they had fought a war with them, so it is unknown when first contact between Cardassia and the Federation was.