I would like to cancel my Creative Cloud single-app membership for Illustrator

Keep in mind that if you cancel an annual subscription before your 12th month of service, there's a 50% early termination fee.

How do I Cancel my Subscription?
https://helpx.adobe.com/manage-account/using/cancel-subscription.html
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Subscription & Cancellation Terms:
https://www.adobe.com/legal/subscription-terms.html

I've moved this from the Using the Community forum (which is the forum for issues using the forums) to the Account, Payment, & Plan forum

See here:

https://helpx.adobe.com/manage-account/using/cancel-subscription.html