We've done this with real-world PRs from our code base (chosen from a project that matches the job they are interviewing for), especially for more senior devs i

We've done this with real-world PRs from our code base (chosen from a project that matches the job they are interviewing for), especially for more senior devs it is good to see how they parse through the code, what they look for, comments they make, and how they communicate. The one thing I didn't feel just asking for review/discussion accounted well for was their ability to build/add something new to the code, and so we have followed up the code review/discussion with a very specific/small exercise to evaluate the process (architecture, pseudo-code) they'd use to do that, and then discuss that as well.