Studies of neutrino oscillations entered a precision era. One of the hot topics in the neutrino oscillations is the measurement of the phase which corresponds to CP symmetry violation/conservation in the neutrino sector (CP phase). CP phase is currently the least precisely known neutrino oscillation parameter and reduction of the systematic uncertainties is a must for its determination. Dominant systematic uncertainty in such measurement arises from mis-modelling of neutrino interactions.
In the talk I will discuss the problems in modelling of neutrino-nucleus interactions in the GeV energy region and the relations between the precise neutrino oscillation studies and neutrino interactions. I will also present the results of the measurements of cross sections for neutrino-nucleus interactions in the energy region mentioned above. Talk has a particular focus on the studies reported by T2K collaboration. Finally, I will briefly present the future plans to perform neutrino cross-section measurements in the T2K experiment.