https://www.techradar.com/news/iphone-xr-vs-iphone-8

The iPhone XR is in a way the start of a new range from Apple, falling somewhere between the iPhone 8 and the iPhone XS, but it's the iPhone 8 that it's the clear successor to.

Their designs differ, as do many of their specs and features, but the iPhone XR is the cheapest of Apple's new handsets, just like the iPhone 8 was last year.