Theory overview of tree-level $B$ decays

I describe the theoretical progress in the study of semileptonic tree-level B decays, and its interplay with recent experimental results. In particular, I focus on two anomalies: the ratios $R(D^{(*)})=displaystylefrac{{cal B}(B to D^{(*)} tau bar u_tau)}{{cal B}(B to D^{(*)} ell bar u_ell)}$ and the inclusive versus exclusive determination of $|V_{cb}|$. I review a few explanations proposed for such anomalies, and discuss tests to shed light on their origin.