The Korean Wasabi Mango is the first 4K IPS panel to support 120Hz refresh rates.

43" Wasabi Mango UHD430 is World's First Commercially Available 120 Hz, 4K  Gaming Monitor | TechPowerUp
Wasabi Mango UHD430

The UHD430 is additionally being marketed with HDR support, though it’s the entry-level 400 nits brightness achieved here. Some high end panels are now offering very bright 1000 nits but there are not many of them available yet.

  • UHD430
  • 3840×2160 120Hz
  • 400 nits
  • 1200:1 contrast
  • 4:4:4 chromaticity support
  • 3x HDMI, 2x DisplayPort

Realistically this panel needs DisplayPort 1.4a support to be able to handle the bandwidth needed.

I am expecting to see more 120Hz panels to become available over the next few years as gaming demands for faster action are pervasive.