Parton densities PDFs are most important objects both from a fundamental point of view, for characterising the partonic content of hadrons and nuclei, and for the application of collinear factorisation in hadronic and nuclear collisions. Nuclear parton densities nPDFs are greatly unknown, compared to those in the proton, due to the scarcity of experimental data. In this contribution I will first review the present status of nPDFs. Then I will discuss the perspectives of further determining them in presently existing experiments, particularly in pPb collisions at the LHC. Finally I will examine the possibilities that planned experiments, both hadronic machines - HL-LHC - and electron-nucleus colliders - EIC, LHeC and FCC-eh, offer for constraining nPDFs.