Pandoc is a markup converter which can output LaTeX and can parse a subset of LaTeX. Questions about pandoc itself are not on-topic for this site; questions about using it to produce LaTeX are on-topic.
Pandoc is a markup converter which can convert between a variety of markup formats. It is capable of outputting LaTeX and ConTeXt, and it is possible to use a limited amount of LaTeX syntax in its input.
As pandoc is not a TeX program, questions about pandoc itself are not on-topic for this site. As pandoc can be used to produce LaTeX, questions about how to handle that output are on-topic.
As an example of an on-topic question, since pandoc is producing the output it is often desirable not to edit the output itself. Thus one may wish to redefine certain macros so that the result of running TeX on the pandoc output changes without having to change the output from pandoc.
For more information on pandoc, see http://johnmacfarlane.net/pandoc/index.html.