Today (May 17, 2019), Sprint has begun taking pre-orders for its first 5g devices. They are the LG V50 ThinQ and HTC's 5G hub. These products are only available in certain regional markets, however.
https://www.notebookcheck.net/Sprint-launches-pre-orders-for-the-LG-V50-ThinQ-and-HTC-5G-Hub.420812.0.html