ZTE is expected to announce their ZTE Gigabit at MWC 2017 alongside some other smartphones.
The Chinese company describes the phone as a "forward-looking smartphone" for 5G era, although we won't see the successor to 4G LTE in wide usage until 2020.
The phone will allow for 1 gigabit per second download speeds. ZTE believe that this feature will improve 360 VR videos, streaming, and more.
Because this phone is coming out this year, it is very unlikely to have anything to do with actual 5G. However, companies like Qualcomm do have modems capable of Gigabit speeds already.
I would expect that this ZTE device will feature either Qualcomm's Snapdragon 835 or their Snapdragon X16 modem. Both of these have Gigabit LTE capability.
Unfortunately, not much is known about the phone, so we don't know the specs or the price.