Although it may not be realistic, Facebook is evidently saying its operations in Europe may be in question, unless European data protection regulators back down.
The point at issue is that Ireland’s Data Protection Regulator wants to stop the transfer of data about European citizens to servers in the US, following concerns about the US government surveillance of the data (this is part of what Schrems II was about).
Facebook is citing various objections including a lack fairness and an impossible timescale, but there is an important underlying point here.
Many organisations rely on moving personal data around the world quickly and easily, in the name of targeting us with ads. With Privacy Shield having been declared invalid recently, and growing concerns about how some governments access personal data in ways which are not compliant with GDPR, it will be very interesting to see how this develops.
And of course, here in the UK we are subject to the same regulations, so perhaps our own regulator the ICO will take a position soon?