It seems that there are two possibilities, both of which are related to transferring your markdowns through a LaTeX style file as follows:
pandoc -H format.sty -o foo.pdf bar.md
Beamer - . Beamer. enumitem - . , , :
\usepackage{enumitem}
\usepackage{amsfonts}
\setlist[itemize,1]{label=$\bullet$}
\setlist[itemize,2]{label=$\diamond$}
pandoc PDF, LaTeX \begin{document}.