jats:pExploring the QCD phase diagram through relativistic heavy-ion collisions is a primary goal of modern nuclear physics. This contribution focuses on fluctuations and correlations of conserved charges — specifically net-baryon and net-charge cumulants — as sensitive probes of the phase structure and the QCD critical point. We discuss recent theoretical and experimental advancements, highlighting constraints from lattice QCD and new results from the RHIC Beam Energy Scan program. Key challenges in theory-to-experiment comparisons at high baryon density are discussed, alongside the systematic requirements for meaningful physical interpretation. Finally, we identify open issues and outline the discovery potential of future low-energy experiments, such as CBM, in resolving the high-density regime of the phase diagram.</jats:p> jats:sec jats:titleAbstract</jats:title> jats:supplementary-material jats:permissions jats:copyright-statementPublished by the Jagiellonian University</jats:copyright-statement> jats:copyright-year2026</jats:copyright-year> jats:copyright-holderauthors</jats:copyright-holder> </jats:permissions> </jats:supplementary-material> </jats:sec>