  For the determination of the Cabbibo-Kobayashi-Maskawa matrix element
$|V_{cb}|$ from inclusive data a precise knowledge of the semileptonic $b \to
c$ decay rate is necessary. Since this observable has a bad convergence
behavior when the heavy quark masses are expressed in the on-shell or
$\overline{\text{MS}}$ scheme the latest determinations have been obtained in
the so called kinetic mass scheme. The relation between the different schemes
needs to be known to high precision as well. In this proceedings we present our
recent calculations which push the precision of both ingredients to
$\mathcal{O}(\alpha_s^3)$. The results can be used to improve the inclusive
determination of $|V_{cb}|$.
