NikonRumors released Nikon Z8 with Z7, Z9 and D850 body size comparison.

▲ D850 vs. Z8 vs. Z9
For reference, the Nikon Z9 body size is about 149 x 149.5 x 90.5mm, the Nikon Z7 body size is about 134 x 100.5 x 67.5mm, and the Nikon D850 body size is about 146 x 124 x 78.5mm.

▲ Z7 vs. Z8 vs. Z9
The newest addition to the lineup is a new model of the Nikon Z8, which is said to be similar in size to the D850, but will be slightly thinner than the D850 because the Z8 is a mirrorless camera.

briefly organized a summary of some of the previous Nikon Z8 related news.
- Z8 is a combination of Z7 and Z9
- Body size is similar to the D850
- Improved EVF
- Same sensor as Z9
- Some of the Z9’s features will be devolved to the Z8
- Expected to be released in April and shipped in May
- Uses the same EN-EL15c battery as the Z7
- Battery grip support
- 8K 60 fps video
- Dedicated USB-C power port for charging/continuous use
- Body or kit €4,500 (currently about RMB 33,210)