They're sharing a lot of the resources as pragmatically as possible it seems. GH Actions and DevOps workflows are really similar, and afaik run on the same clusters of hardware.

There's also some pretty decent integration features for DevOps projects with source control in GitHub for that matter iirc. Not to mention the potential upsell to/from GH Enterprise and/or Azure DevOps.

I can imagine at some point, GH Enterprise and Azure DevOps may become more similar and share more infrastructure over time.