  We report on a new calculation of the next-to-next-to-leading order (NNLO)
QCD radiative corrections to the inclusive production of top-quark pairs at
hadron colliders. The calculation is performed by using the $q_T$ subtraction
formalism to handle and cancel infrared singular contributions at intermediate
stages of the computation. We present numerical results for the total cross
section in $pp$ collisions at $\sqrt{s}=8$ TeV and $13$ TeV, and we compare
them with those obtained by using the publicly available numerical program
Top++. Our computation represents the first complete application of the $q_T$
subtraction formalism to the hadroproduction of a colourful high-mass system at
NNLO.
