The Pixel had a very good camera, and Google aimed to continue that trend with the launch of the Pixel 2. One of the ways it did that was with enhanced HDR+, which was made possible with the Pixel Visual Core processor. The only problem was that it wasn't available to use in third-party apps, but that's finally changing.
Google has announced that an update activating the Pixel Visual Core processor will be rolling out to Pixel 2 owners over the coming days, which should help improve any pictures you take via Instagram, WhatsApp, Snapchat, or whatever else. HDR+ has been available in the main Pixel camera since last year, but this means apps will be able to access the extra processor directly, rather than going through the application processor.
Presumably the changes will only apply to apps that actually opt in to use the processor, so don't expect this to be a universal thing as soon as the update arrives on your phone.
The Pixel Core Processor itself has been designed to do a bunch of the heavy lifting when it comes to processing pictures, but importantly uses less power than conventional means. So not only are you improving the quality of your pictures, Google claims it saves you precious battery life in the process. Those improvements are done thanks to machine learning, which Google is quite fond of these days. Other features include zero shutter lag, and RAISIR which improves the quality of pictures you take while the camera is zoomed in.