Since its first use by Gell-Man in 1971, “flavour physics” denotes physics of transitions between the three generations of the Standard Model fermions. The quark sector is described by a single unitarity matrix, the Cabibbo Kobayashi Maskawa (CKM) matrix, whose elements have to be measured analyzing suitable decay processes. Also, the violation of the CP symmetry is closely related to flavour physics, even though the CKM mechanism for the CP is unable to account for the observed baryon asymmetry of the universe through the baryogenesis. A the beginning of this century, the spectacular performance of the B-factories allowed the BaBar and Belle experiments to reach a deep understanding of the CP violation phenomena providing a striking confirmation of the CKM-paradigm of CP violation. With the start of LHC, the harvest of measurements performed by LHCb marked the triumph of the CKM picture. A large fraction of LHCb data has still to be analysed looking for subleading effects of physics beyond the SM. In this seminar I’ll give an overview of the flavour physics and of the CKM matrix, with particular emphasis on results from B physics and the performance of the LHCb detector: what we learnt in the past, what could be found in already collected data and what we can expect from Belle 2 and LHCb-Upgrade experiments which will take data in the coming years.