  Heavy flavor physics entered a new era when the Belle II experiment observed
its first collision. There are several hints found so far by BaBar, Belle, and
LHCb in particular, that suggest the physics beyond the Standard Model
appearing in the loop processes at short distances. They will be further tested
by higher precision experiments in the coming years, while the role of lattice
QCD is to understand the long-distance physics quantitatively so that one can
unambiguously isolate the short-distance physics from the experimental data. I
summarize the status towards this goal and then look at the challenges we are
facing.
