https://wccftech.com/download-the-pixel-3-google-camera-port-for-the-oneplus-6/

The Google Pixel 3 comes with a new version of the Google Camera app which brings a new UI with new swipe gesture-based navigation. Features such as Top Shot, Motion Tracking Autofocus, Auto Frame Rate in video recording and the upcoming Night Sight feature for low light photos are exclusive to the Pixel 3 for the moment. Several ports of the Pixel 3’s camera app are being developed at the moment for a wide array of devices.

Developers have managed to enable Night Sight for devices such as the Xiaomi Mi 5 and the Essential Phone. Additionally, the Pixel 3 Google Camera port was developed for the Xiaomi POCO F1 and the Xiaomi Mi 8. Now, a stable Pixel 3 Google Camera port has been developed by an XDA Developers user for the OnePlus 6. Features such as Night Sight, Slow motion, Photobooth, Top Shot, zoom in portrait mode and resampling have been disabled owing to compatibility issues. Some of the features require Pixel 3 hardware to operate, so the likelihood of them working on other devices is low.