While this might sound like the old Office Space gag that they "take the specs from the customers and bring them to the engineers", a good PM brings a lot of value to the team and - in the classical PM role - frees up the engineers to worry about implementation and less about what this message should say when this error happens.
But a great PM will come up with product strategy and just do whatever needs to be done to get the software out the door. Sometimes this means working closely with lawyers. Sometimes this means working closely with the security team. Sometimes this means writing code. Or making sure the marketing team is on the same page as the product team. Or that the sales team knows how to pitch this and has all the materials they need to present. Or presenting to customers at conferences.
Sometimes this means baking cupcakes for the team, just because.
It's a time consuming, unenviable position in a lot of ways. But it's also probably the position at Microsoft with the most ability to impact products that ship to customers.
(Disclaimer: Microsoftie.)
- Ex MSFT PM
PM refers to Project Manager as far as I know. But there are different levels of PM's within Microsoft. You can be a completely junior PM managing two really junior devs developing a simple feature. Or you can be a principal level PM and earn that amount of money. Just the term PM doesn't mean much.