  We present our recent progress on the relativistic modeling of
neutrino-nucleus reactions for their implementation in MonteCarlo event
generators (GENIE, NEUT) employed in neutrino oscillation experiments. We
compare charged-current neutrino and antineutrino cross sections obtained
within the SuSAv2 model, which is based on the Relativistic Mean Field theory
and on the analysis of the superscaling behavior exhibited by ($e,e'$) data. We
also evaluate and discuss the impact of multi-nucleon excitations arising from
2p-2h states excited by the action of weak forces in a fully relativistic
framework, showing for the first time their implementation in GENIE and their
comparison with recent T2K data.
