After a coffee break I was able to answer it. :D
Still thank you for your help!!

\documentclass[11pt]{report}
\usepackage{graphicx}
\usepackage[printonlyused,nohyperlinks]{acronym}
%%%% Confusion Matrix Body %%%%
\newcommand\MyBox[1]{%
\fbox{\parbox[c][3cm][c]{3cm}{\centering #1}}%
% Size of boxes
}
\newcommand\MyVBox[1]{%
\parbox[c][1cm][c]{1cm}{\centering\bfseries #1}%
}
\newcommand\MyHBox[2][\dimexpr3cm+2\fboxsep\relax]{%
\parbox[c][1cm][c]{#1}{\centering\bfseries #2}%
}
\newcommand\MyTBox[4]{%
\MyVBox{#1}
\MyBox{#2}\hspace*{-\fboxrule}%
\MyBox{#3}\par\vspace{-\fboxrule}%
}
%%%%
\newcommand*\rot{\rotatebox{90}}
\begin{document}
\begin{acronym}
\acro{TP}{True Positive}
\acro{FP}{False Positive}
\acro{TN}{True Negative}
\acro{FN}{False Negative}
\end{acronym}
\begin{figure}
\begin{center}
{
\offinterlineskip
\raisebox{-6cm}[0pt][0pt]{
\parbox[c][5pt][c]{1cm}{\hspace{-4.1cm}\rot{\textbf{Actual}}\\[20pt]}}\par
\hspace*{1cm}\MyHBox[\dimexpr3.4cm+6\fboxsep\relax]{Predicted}\par
\hspace*{1cm}\MyHBox{Cancelled}\MyHBox{Not Cancelled}\par
\MyTBox{\rot{Cancelled}}{\ac{TP}}{\ac{FN}}
\MyTBox{\rot{Not Cancelled}}{\ac{FP}}{\ac{TN}}
}
\end{center}
\end{figure}
\end{document}
Because I am interested is there a better way to make Actual aligned in the middle with the same distance as Predicted. (My solution was try and error)