Tomorrow (March 28) Tamron will announce a new 28-75mm f/2.8 Di III VXD G2 lens for Nikon Z-mount. Stay tuned for the details:
Previous coverage of Tamron lenses for Nikon Z-mount can be found here.
The Tamron 28-75mm f/2.8 lens already exists for Sony E-mount and is currently priced at $799 after a $100 rebate (Adorama | Amazon | B&H) – expect the Nikon version to be around the same price range:
Nikon already has the Nikon NIKKOR Z 28-75mm f/2.8 lens for $1,000 after a $200 rebate (Adorama | Amazon | B&H) that is based on the Tamron lens:
Nikkor Z 28-75mm f/2.8 lens additional coverage (the first Tamron lens for Nikon Z-mount)