Create a table with double title - pdf

Question

I have this code to create a table, but I want to create a table like the image below. How can I modify the code to create the table?
\begin{tabular}{|l|l|l|l|l|}
\hline
& AB & A & B & O \\ \hline
AB & 0 & 1 & 1 & 2 \\ \hline
A & 1 & 0 & 2 & 2 \\ \hline
B & 1 & 2 & 0 & 2 \\ \hline
O & 3 & 3 & 3 & 0 \\ \hline
\end{tabular}
\end{table}

Answer 1

\documentclass{article}
\usepackage{multirow}
\begin{document}
\begin{table}
\centering
\renewcommand{\arraystretch}{1.5}%
\begin{tabular}{c c *{4}{| c} |}
& \multicolumn{1}{c}{} & \multicolumn{4}{c}{Classified As} \\
& & AB & A & B & O \\
\cline{2-6}
& AB & 0 & 1 & 1 & 2 \\
\cline{2-6}
\multirow{2}*{\renewcommand{\arraystretch}{1}%
\begin{tabular}{#{}c#{}}
True \\ Blood \\ Type
\end{tabular}} & A & 1 & 0 & 2 & 2 \\
\cline{2-6}
& B & 1 & 2 & 0 & 2 \\
\cline{2-6}
& O & 3 & 3 & 3 & 0 \\
\cline{2-6}
\end{tabular}
\end{table}
\end{document}

Answer 2

Hopefully easy:
\documentclass{article}
\usepackage{multirow}
\begin{document}
\begin{table}
\centering
\begin{tabular}{cc|c|c|c|c|}
& \multicolumn{1}{c}{ } & \multicolumn{4}{c}{Classified As} \\
& & AB & A & B & O \\ \cline{2-6}
\multirow{4}{11mm}{True Blood Type} %
& AB & 0 & 1 & 1 & 2 \\ \cline{2-6}
& A & 1 & 0 & 2 & 2 \\ \cline{2-6}
& B & 1 & 2 & 0 & 2 \\ \cline{2-6}
& O & 3 & 3 & 3 & 0 \\ \cline{2-6}
\end{tabular}
\end{table}
\end{document}
The above MWE outputs the following table:
This first sketch can then be improved aesthetically in several ways!