I have heard if someone calls your iPhone you can pick up the phone call on your Mac. Is this also the case if a landline calls your cell? Can you also make outgoing calls so people think you're using your phone and not your Mac? Is this free?
I don't think so, apple loves their tight ship.
My Dell XPS 13" can receive calls which i never used
anyways from .com:
iPhone Cellular Calls
iPhone Cellular Calls requires any iPhone using iOS 8.1 or later and an activated carrier plan. You can then relay calls to and from that iPhone from these devices:
• Any Mac using OS X Yosemite or later. Mac mini and Mac Pro require an external microphone or headset.
• Any iPhone, iPad, or iPod touch using iOS 8 or later.