  We report on recent results obtained by the Belle II experiment related to
searches for beyond-the-standard-model physics. The $B$ meson decay data sample
used corresponds to an integrated luminosity of $L = 189$ fb$^{-1}$. In recent
years, discrepancies from standard-model predictions, which suggest violation
of lepton-flavor universality, have emerged in multiple measurements of
$B$-meson decays. In this document two analyses aimed to search for violation
of the light-lepton universality are reported: the inclusive $R(X_{e/\mu})$
measurement and an angular analysis of the $B^0 \to D^{*-} l^+ \nu_l$, with
$l=e,\mu$, decays. In addition, beyond-the-standard-model physics can manifests
itself with the production of new particles. The search for a long-lived spin-0
particle in $b\to s$ transitions, and its interpretation in two dark sector
models, is reported.
