cancel i Tunes

iTunes itself has no real subscriptions. It's a free Application What exactly are you trying to cancel?

Apple Music, Apple TV+, iCloud etc... are subscriptions you can have and should show up under your Apple ID if you started said subscription directly yourself on your Apple ID.

If you are the Family Organizer in Family Sharing, then you may get charged for other family member's subscriptions, but they would be listed under their Apple ID, not yours and would need to be cancelled from their accounts.

That's probably iCloud storage space. Follow the steps here: link-> Downgrade or cancel your iCloud+ plan - Apple Support

Hello ~ Take a look here:

Subscriptions and Billing - Official Apple Support

~Katana-San~