Nitric acid is an oxidising agent and reacts with PbO but it does not react with PbO2. Explain why?

PbO is a base. It reacts with nitric acid and forms soluble lead nitrate.
$\mathrm{PbO}+2{\mathrm{HNO}}_{3}\to \underset{\mathrm{soluble}}{\mathrm{Pb}{\left({\mathrm{NO}}_{3}\right)}_{2}}+{\mathrm{H}}_{2}\mathrm{O}$ (acid base reaction)
Nitric acid does not react with PbO2. Both of them are strong oxidising agents. In HNO3, nitrogen is in its maximum oxidation state (+5) and in PbO2, lead is in its maximum oxidation state (+4). Therefore, no reaction takes place.