For the given cell, anode is $\mathrm{Cd}$ and cathode is Ag.
$\begin{aligned}
\mathrm{E}_{\text {cell }}^{\circ} & =\mathrm{E}_{\text {cathode }}^{\circ}-\mathrm{E}_{\text {anode }}^{\circ} \\
& =0.799-(-0.403) \\
& =1.202 \mathrm{~V}
\end{aligned}$