Lattice $B\to D^{(\ast )}$ form factors, $R(D^{(\ast )})$, and $\mathrm{\mid }{V}_{cb}\mathrm{\mid }$

I discuss recent progress in lattice calculations of $B\to D^{(\ast )}\mathrm{\ell }\nu$ form factors, important for the precision determination of $\mathrm{\mid }{V}_{cb}\mathrm{\mid }$ in the Standard Model (SM), and for testing SM expectations of lepton flavor universality in observables $R(D^{(\ast )})$. I also discuss progress in calculations of the related $b\to c$ semileptonic decays $B_s \to D_s^{(*)} \ell \nu$and$B_c \to J/\psi , \ell \nu$ now experimentally accessible at the LHC.