The charm sector provides new and unique insights into flavor and BSM physics, complementing longstanding programs with kaons and B-mesons. We report status and  progress in null test searches from theory on rare decays of charm mesons and baryons into invisibles, photons and leptons, and where flavor experiments are currently pushing this frontier. We also discuss CP-violation together with sizable U-spin violation seen in hadronic 2-body decays at the LHCb-experiment. A stunning explanation of this puzzle is given by a light, hadrophilic Z-prime that can also resolve issues with the pion-form factor in J/psi-decays.