\documentclass[border=2pt]{standalone}
\usepackage{tikz}
\usetikzlibrary{3d}
\begin{document}
\begin{tikzpicture}[x=0.5cm, y=0.5cm, z=0.3cm]
  \draw[thick,->] (0,0,0) -- (4,0,0) node[anchor=north east] {$x$};
  \draw[thick,->] (0,0,0) -- (0,4,0) node[anchor=north west] {$y$};
  \draw[thick,->] (0,0,0) -- (0,0,4) node[anchor=south] {$z$};
  \draw (2,2,0) -- (2,2,2) -- (0,2,2) -- (0,2,0) -- cycle;
  \draw (2,0,2) -- (2,2,2) -- (0,2,2) -- (0,0,2) -- cycle;
\end{tikzpicture}
\end{document}
