The Z50 II is Nikon's compact DX (APS-C) mirrorless camera, aimed at travel, family and content creators. It has no in-body stabilisation, so Tamron's VC lenses are a good match, and full-frame Z lenses work on it with a 1.5x crop.
On the Nikon Z50 II, every lens gives a field of view about 1.5x narrower than its focal length suggests. Below, each lens shows its full-frame equivalent on this camera. Tamron's APS-C lenses (Di III-A and the 16-50mm) are designed for this sensor size; its full-frame lenses fit too and become longer, which helps for portraits and wildlife.
The camera has no in-body stabilisation, so lenses marked VC (Tamron's Vibration Compensation) give steadier handheld photos and video.
Where to start
For most Nikon Z50 II owners the best first Tamron lens is the Tamron 17-70mm F2.8 Di III-A VC RXD (B070): it is a bright 26-105mm equivalent everyday zoom with VC to make up for the body's lack of stabilisation.