Hadron structure study in forthcoming Drell-Yan experiments

The study of Drell-Yan (DY) processes involving the collision of an (un)polarised hadron beam on a (un)polarised proton target can result in a fundamental improvement of our knowledge on the transverse momentum dependent (TMDs) parton distribution functions (PDFs) of hadrons. The production mechanism of $J/\psi$ and $J/\psi$ - DY duality can also be addressed. One of the forthcoming polarised DY experiments (COMPASS (SPS, CERN)) is discussed in this context. The most important features of this project are briefly reviewed, as well as its sensitivity to the various transverse momentum dependent spin asymmetries.