  We present the calculation of QCD radiative corrections to heavy-quark
production at NNLO. The calculation is implemented in an updated version of
\textsc{Matrix}, which allows us to obtain multidifferential predictions for
stable top quarks. We also report on the NNLO calculation for $b{\bar b}$
production and comment on the inclusion of top-quark decays and of the
extension of our results to $t\bar tH$.
