Over the past decade, measurements involving the flavour changing neutral current transition $b\to s\ell^+\ell^-$ have shown tantalising tensions with Standard Model (SM) predictions. However, our current understanding of the hadronic uncertainties in these predictions hinders our ability to interpret these as physics beyond the SM. In order to resolve this impasse, measurements of observables that are theoretically pristine in processes that are accidentally suppressed in the SM are of paramount importance. Observables in $B^0_{s}\to\mu^+\mu^-$ decays as well a lepton flavour universality tests in $B^+\to K^+\ell^+\ell^-$ transitions are perfect examples of such measurements. In this mini-workshop, we will present the latest results in $B^0_{s}\to\mu^+\mu^-$ decays and the updated measurement of $R_K=BR(B^+\to K^+μ^+μ^−)/BR(B^+\to K^+e^+e^−)$ using the complete dataset collected by the LHCb experiment, and we will discuss the theoretical implications.