http://www.techradar.com/news/mac-pro-2018-release-date-news-and-rumors

Apple’s Mac Pro has gone for several years without a considerable upgrade or update, but that changes this year. Finally, back in April 2017, Apple responded to the outcry for support of the Mac Pro in teasing that it is working on an ‘upgradeable’ and ‘modular’ Mac Pro 2018 model.

The firm then backed up its promise of a new Mac Pro with a reminder hidden within a press release for the iMac Pro sale date back in December 2017. So, we already know that a Mac Pro is actively under development and could release before the end of this year.