Looks like no strings attached: https://community.carbide3d.com/t/carbide-create-pro-free-for-a-year/20918
"We’re trying to find extra value we can provide to the Carbide 3D community, who might have a lot of extra time on its collective hands, and we thought this might a good distraction for people stuck at home and it might give users who sell products a way to level-up their offerings.
Go to https://launch.carbide3d.com/promo and claim your free one year license for CC Pro. If you’re not logged in you’ll need to do so and then visit the link again."
EDIT: Here’s a list of what you get with Pro: https://carbide3d.com/carbidecreate/pro/