Our dependence on foreign tech company like Microsoft is pretty concerning, especially for applications which attract spies like international politics, defence industry and more.
I know, Office integration with One-drive is amazing, but the report about the next gen european fighter jet or the internal e-mail of top level politicians and their staff have nothing to do on the computers of a foreign company.
It's not just that Microsoft is a foreign company. US law requires them to hand out customer data to the US intelligence services. So, this isn't a matter of caution. We know that they are leaking data.