VS Code becoming standard tools, alongside GitHub and NPM which they own now. This affords a tremendous amount of steering control and opportunities for lock-in. Some of the existing ones are the proprietary plugins for VSC, and GitHub Actions.

I wouldn't be surprised if they end up picking up Docker for a song now that Docker has utterly failed to find a workable revenue model. (Microsoft sponsored Docker's surprisingly-complete Windows support, IIRC.) The extremely-widely-used Docker Desktop products are already nonfree, as well as the dockerd that runs on Windows.