Officially not named as the successor to OpenGL, but in practice it is.
Aims to offer better support for multithreading.
Ranked in these QuestionsQuestion Ranking
Pro Easy learning curve
It is very easy to get started. Just look at spec and make graphics. No programming, math or GPU hardware knowledge requiered to use it. Power Point is too complicated for presentation? Try Vulkan API!
It is supported by Linux, Windows, some *nix. For Mac there is MoltenVK working on Metal.
Pro Low API overhead
In OpenGL, DirectX it is higher.