# math inside title in tcolorbox

I am writing a script to emulate a mathematica notebook with tcolorbox in latex.

it seems to be perfectly ok as long as I do not have an equal sign in the title. If I do, it breaks

\begin{tcolorbox}[title=$a=b$,title filled]
$$a=5$$
\end{tcolorbox}


\documentclass{article}
\begin{tcolorbox}[title={$a=b$},title filled]
$$a=5$$