There was some mention that a new "Apple-designed" display might be released when the new Mac Pros come out. But that probably won't be until next year at the earliest.
And even though the design might be Apple's, they may farm out the actual construction to another company, like they did with the LG 5k and 4k displays.
I see little "added value" in buying an Apple-branded display, in any case.
There are MANY 3rd-party displays out there that will be cheaper, and yield an image that will be equal to Apple's ... or even better.
Then again, some folks just have to have that "apple logo" on everything they use. (I ain't one of 'em)