Hi therepatjonesny,
Thanks for joining us in Apple Support Communities! We understand you're asking if you'll be refunded for your existing Apple Music subscription when signing up for Apple One. We're glad you're here, and we can provide some guidance.
You can sign up for a free 30-day trial of Apple One, and after the trial, the subscription will be billed monthly. Upon renewal, you won't be charged for any active individual subscriptions included with Apple One. If you're charged for your Apple Music subscription during your Apple One trial, you’ll receive a pro-rated refund for the paid Apple subscription when Apple One renews at the end of the trial.
“If Apple One costs less than your current subscriptions, you will not get a free trial so that you can immediately start saving money.” Have a look at this link to learn more:
Bundle Apple subscriptions with Apple One
We hope this information is helpful. Don’t hesitate to let us know if you have any more questions.
Cheers.