For a few years now, Linux has had KDE/GSConnect, which adds in basically all of the MacOS/iPhone handoff functionality to your Linux distro/WM of choice, with a few extra tools that go beyond even what Apple has.

For starters, there's the basic stuff: desktop messaging, contact synchronization, integrated wireless filesharing, universal clipboard/notifications and battery updates for your connected device.

Then it also has some features that don't exist on MacOS/iOS: you can set up macros on your computer and easily remotely execute them with the press of a button on your phone, use your phone as a wireless trackpad, synchronize media controls across all your devices, use your phone as a keyboard for your computer, use your computer as a keyboard for your phone, wirelessly mount your phone as a webcam, ring it at max volume if you lose it, and sharing links.