Interesting naming, I wonder if we can read anything into the specs regarding these names, I'll give it a go:
GTX 1170 & GTX 1180: these might be the existing Pascal architecture just on 12nm rather than 14nm, with increased clocks and cores - i.e. not having ray tracing nor tensor cores.
RTX 1070 & RTX 1080: these could be a cut down version of the new desktop Turing architecture. Turing architecture uses more power than Pascal, so that's why they would need to cut it down for mobile. RTX obviously referencing the ray tracing & tensor core aspects of the new Turing architecture. So these would have less cores and lower clocks than the desktop RTX 2070 & 2080.
This could end up in the curious situation of the GTX 1170/1180 cards having more brute gaming power than the RTX 1070/1080, due to the fact that the RT cores & Tensor Cores have a high power usage budget; also, we're in the somewhat confusing numbering scheme that 1170 is a bigger number than 1070, so the GTX version has a bigger number associated with it, which maybe supports that it could have more brute gaming power. This would seem like a strange trade off though, as it seems counter-intuitive that the new RTX cards would have less gaming power than the more basic & older tech GTX cards.
All just some thoughts!