Semileptonic and Leptonic Decays at Belle II

This proceeding summarises recent studies on semileptonic and leptonic $B$ decays, which provide stringent tests of lepton flavour universality as well as key experimental inputs to ultimately increase the precision of inclusive $|V_{ub}|$ and $|V_{cb}|$ determinations. The presented analyses investigate electron-positron collision data recorded by the Belle and Belle II detectors at the $\Upsilon(4S)$ resonance, comprising the complete Belle data set of 711 fb$^{-1}$ and 365 fb$^{-1}$ of Belle II data samples collected between 2019 - 2022.