The last time Sony and Nikon sensor pixel counts were the same on their high end MP camera, was when the A7R and the D800 both had 36 mpixels, in 2012-2013. So there is a good chance, Nikon is working on a different pixel count, for their upgraded sensor. Whether its a slightly higher or minimally lower pixel count remains to be seen. If it happens, it'll be in 2020. I say if, because Nikon isn't very sure footed when it comes to mirrorless. The Z series is really good, but there are faults in the system when compared to other mirrorless systems such as Sony and Fujifilm. Even Canon, who screwed the pooch with the EOS R, is making its system viable with mostly professional RF lenses. I don't think Nikon knows what their next step is.
Rich Rosen
https://www.flickr.com/photos/richardrosenphotography
what kind of faults in the Z-system you mean? The Canon RF lenses are not better - eg than a 24-70 f2.8S - and the lens roadmap of the Z will fill the gaps in 12-18 months ...
No,they're not. However the Nikon 2.8s is the only pro level lens the Z line has. Canon has a 50 1.2, two 85 1.2, a 28-70 f2, who's build quality is designed to take beating and keep on ticking, already announced. The case can be made, that Nikon's S line has excellent characteristics, but most of the offerings cannot be considered Nikon pro line. Many are awaiting the 1.4s which would be considered a pro line of primes. Personally I do not consider the 1.8s primes, or the f4 zooms to be professional grade, but they are certainly excellent lenses. The Nikon 58 f.095 Noct, which could be considered professional, it is nothing more than a phantom product that was announced months ago, hasn't materialized. Nikon chose to go after the prosumer market, rather than the pro market with their Z cameras and lenses. Canon is choosing to go after the pro market with its lens offerings. Nikon will get there, but after Canon, and of course Sony. I believe they chose to do this in a total reversal of their product philosophy. In the past, the lead Nikon product has always been their top line camera, mated with a professional grade lens. The F, the F2, ...the D1, ...D3. The D1 series was mated with the 17-35 f2.8 AF-S, The D3, was mated with the 24-70 f2.8. But the Z7 has the 24-70 f4??? They're hedging their bet on mirrorless.