I think my current KIA car has a slot in the infotainment unit for a CD but like the one in the glove box of my previous Golf and Seat Leon I never used it other than just checking it worked when first collecting the car from new.
That’s why I say “I think” as to myself and a lot of other folk these days its become obsolete.
In my Golf I used a standard 16 Gb SD card and in my current car, a 32 Gb mini USB memory stick. Its an easy procedure to put all your music onto some form of memory stick to play in the car and if you use a high byte rate while converting your CD’s you wont hardly notice any different to the sound in a car environment.
I think most of the young ones these days just use the music on their phones via Bluetooth or just stream and that’s why there’s no CD unit in your car IMO.