The current Nikon rebate program (sofortrabatt) in Europe is set to expire next week on September 23rd:
In Germany, you can get 10% off select lenses and up to €500 off Nikon cameras (including the Z8 and Z9).
In the UK, you can save up to £1,900 on selected Nikon gear (including the Z8 and Z9).
The current Nikon USA rebates can be found here: Adorama | Amazon | B&H Photo | Paul’s Photo | Service Photo.