All I've gather about it is that AMD and Intel struggle developing an architecture for it and it is used for mobile phones. Anyone willing to give a in-depth lecture on this or a good link. Preferably not Wikipedia.
This Stack Exchange answer might help.
The TLDR is that it is a completely different CPU architecture from what Intel and AMD produce. It is common on mobile due to its low power consumption and small footprint. Intel has tried previously to compete in the space using the x86 architecture, but failed to get a sizeable foothold. Still, you've probably heard of some devices that did use Intel Atom CPUs, like the Asus Zenfone 2.
IDK if AMD has ever actually attempted to compete in this market.
This is fair; I was lazy.
I should have said something like 'ARM is different from the x86 architecture used in what people typically think of when they talk about Intel and AMD CPUs, such as Intel Core/Pentium series and AMD Ryzen/FX/Athlon series CPUs'.
Lazy question got a lazy answer ;P