The noun (Substantiv/Nomen) Cds is feminine in German. Therefore, the correct definite article in the nominative singular is die. So, you say: die Cds.
(CDs)
Mehrere Compact Discs, ein digitales Speichermedium für Musik, Daten etc.
Multiple Compact Discs, a digital storage medium for music, data, etc.
Ich habe viele CDs in meiner Sammlung.
I have many CDs in my collection.