Intel is already an long-term Arm licensee[1], meaning that they can build and optimise Arm designs for their own use. I'd expect the terms of an Arm IP license restricts them from sublicensing any Intel-optimised Arm designs to foundry customers. If I understand correctly, this deal is Intel Foundries in future being able to offer the implementation of optimised Arm designs to customers.

https://wccftech.com/intel-manufacture-arm-chips/