is there something like css-columns in markdown?
No. Presenting content in multiple columns is a presentation concern, but Markdown is all about content:
Markdown is not a replacement for HTML, or even close to it. Its syntax is very small, corresponding only to a very small subset of HTML tags. The idea is not to create a syntax that makes it easier to insert HTML tags. In my opinion, HTML tags are already easy to insert. The idea for Markdown is to make it easy to read, write, and edit prose. HTML is a publishing format; Markdown is a writing format. Thus, Markdown’s formatting syntax only addresses issues that can be conveyed in plain text.
You've tagged several Markdown processors in your question. Some of them may support columnar output, but others don't (GitHub Flavored Markdown certainly doesn't, for example).
You'll have to specify the processor you're using if you want to talk about columns.