MacRumors published a story that it looks like that the iMac Pro will be discontinued.

iMac Pro No Longer Custom Configurable, Available 'While Supplies Last'

Apple appears to be on the verge of discontinuing the iMac Pro, with the store page for the high-end all-in-one Mac including a "While supplies last" tagline and only the base model with no custom configurations available for purchase. The ‌iMac Pro‌ launched in December 2017, and while there have been a few tweaks to the available configurations over the years, it has received no substantial hardware updates over its lifetime. As a result, we have been recommending for some time that users not purchase the ‌iMac Pro‌ as a high-end standard iMac currently offers a better value.

iMac Pro No Longer Custom Configurable, Available 'While Supplies Last'