Elucidating the nature of the dark sector is a central goal in modern cosmology, and one of the most intriguing topics at the interface between astrophysics and particle physics. In particular, determining the neutrino mass and number of effective neutrino species, the `coldness’ of dark matter, and the nature of dark energy are key science drivers for of all of the ongoing and upcoming large-volume astronomical surveys, and one of the primary targets of future space missions. After a broad cosmological overview, I will discuss the current status of dark sector cosmology and the necessity of going beyond the standard model. I will present novel hydrodynamical simulations and innovative techniques for the cosmic web, and briefly touch upon the lesson learned from the SDSS-IV Extended Baryon Oscillation Spectroscopic Survey (eBOSS). I will then highlight particle physics synergies, and outline a future exciting roadmap towards the quest for a direct detection of the neutrino mass and dark energy with STAGE-IV experiments, focusing on the Dark Energy Spectroscopic Instrument (DESI) and the Rubin Large Synoptic Survey Telescope (LSST).