Open problems in high-mass stellar evolution

Massive stars can roughly be divided into two categories: the one that will become red supergiants at (or shortly before) the end of their life, and those that will become Wolf-Rayet stars.RSG stars are dominated by convection, and experience a very strong mass loss; WR stars also undergo a strong mass loss, though through another process than RSGs.Both convection and mass loss don't arise naturally in 1D stellar evolution codes, so we rely on prescriptions.On top of that, most massive stars live in multiple systems, which increases even more the complexity of the picture.I will review the current status of massive star modelling, the problems we meet and some solutions that could come, either from 3D modeling, or from surveys.