It looks like the end of June would bring a slew of new smartphone releases, such as the Huawei Honor 7 as well as Meizu and their Meizu MX5. As for the ZTE Nubia Z9S, this is set to be a slightly updated version of its current flagship device, the Nubia Z9, that has an extremely slim bezel.
Granted, on paper, it does look as though the only change in the Nubia Z9S would be support for Cat 9 LTE networks, and its predecessor, if you can call it so, happens to be limited to Cat 4 LTE. What is the difference between those two categories? Theoretical download speeds, of course, with Cat 4 maxing out at 150Mbps, while Cat 9 LTE maxes out at 330Mbps. If your carrier does not support such insane speeds, it would just make you feel good on paper, that is all.