Let's take my experience.
On Saturday I built a new Skylake PC. I already had Boot a Camp installed on my Mac Pro. When I tried to activate Windows 10 on the Skylake I was not allowed to even though I signed in with my Microsoft account,p.
You can't just 'remove Boot Camp'. Microsoft will not know anything about the installation not being used anymore. There is no deactivation sent to them if you just delete a Boot Camp partition. So you must deactivate.
So I followed the intrusions to deactivate Windows 10 on the Mac Pro, then I could activate the Skylake after one minute.
If you did remove Boot Camp without deactivating Windows and then can't activate in your new computer, just contact Microsoft online chat or by phone and then they will ask some proof of your situation. Then they will deactivate the old install.