More concretely, Microsoft's license [0] gives you at most one of the four essential freedoms:

0. Freedom to run for any purpose? No.

1. Freedom to modify the program? Maybe; Microsoft can revoke it without cause at any time.

2. Freedom to distribute unmodified? No.

3. Freedom to distribute modified? No.

I'm using the free software definition [1] because it's simpler and clearer than the open source definition [2], which is usually considered mostly equivalent in practice, but as far as I can tell Microsoft's license satisfies zero of the latter's ten criteria, apart from perhaps non-discrimination and technology-neutrality. Most of the criteria of the open source definition have to do with distribution, which is not allowed by Microsoft's license.

[0] https://computerhistory.org/blogs/microsoft-research-license...

[1] https://www.gnu.org/philosophy/free-sw.en.html

[2] https://opensource.org/osd