It isn't in of the actual story, but it does have a fantasy aesthetic along with the paradoxical mix of both modern and medieval music, hairstyles, language etc. So it kind of feels like a fantasy...

There are definitely more reasons as to why this anime is iconic! You haven't even met half the main characters yet, and one of them is a fan favourite among lovers of classic anime. Enjoy!

Assuming that you're talking about the Tsubasa anime series (as the manga is complete), it couldn't be completed because it strayed too much away from the manga so CLAMP stopped it and had a different company make 5 OVAs to cover some key moments that the anime series missed. What Tsubasa needs is a full remake like Fruits Basket. The Cardcaptor Sakura sequel anime is also currently incomplete but I still hope it will get another season as the final manga volume just released in the UK this month.