If you've started or joined a Dropbox for Business trial, your Pro subscription will continue during the trial period.
If you convert to a full Dropbox for Business account, your Pro subscription will be canceled immediately, and where possible, any remaining credit will be returned to your original payment method. In-app payments through iTunes or Google Play can't be returned.
If your trial ends and your team does not convert to a Business account, your Pro subscription will continue as-is. You can make further changes (such as plan size) to your Pro subscription once your trial is over.
This article refers to a feature unique to Dropbox for Business. Dropbox for Business is aimed at projects, groups, and other organizations that want to share the same Dropbox storage quota with all of its members. If you're interested in learning more or want to sign up, visit the Dropbox for Business webpage.