  I review the state of the art of the theoretical calculations for decays
mediated by $b\to s \ell^+ \ell^-$ transitions, for $\ell=e,\mu$. I focus on
the predictions of observables in $B\to K \mu^+\mu^-$, $B\to K^* \mu^+\mu^-$,
and $B_s\to \phi \mu^+\mu^-$ decays, as many of these predictions are in
tension with the corresponding experimental measurements. I also briefly
discuss the $\Lambda_b\to \Lambda \mu^+\mu^-$ decay and present a new
calculation for this channel. Special emphasis is placed on the non-local
contributions, as they are the largest systematic uncertainties in these
decays. The current theoretical calculations for $b\to s \mu^+ \mu^-$ decays
are not able to explain the tensions with the experimental measurements.
