The analysis of globular cluster systems (GCSs) in early-type galaxies, spanning from dwarf to massive cluster-dominant systems, reveals fundamental scaling relations that connect the properties of the GCS to those of their host galaxies. Key parameters derived from radial profiles, such as extension, effective radius, core radius, and profile shape, correlate tightly with stellar mass, effective radius, and velocity dispersion. A pivot mass at approximately 5×10^10M⊙ is consistently found across several scaling relations, probably related with the different relevance of mass growth through mergers for galaxies above and below this threshold. Environmental effects play a crucial role in shaping GCS properties. Satellite galaxies in high-density environments exhibit poorer, steeper, less extended, and more compact GCSs at fixed stellar mass compared to their counterparts in lower densities, indicating efficient tidal stripping. In contrast, central galaxies in dense environments show richer and more extended GCSs, likely due to a richer merger history. The inner regions of GCSs show a central flattening in their radial profiles, which is attributed to long-term tidal disruption processes that preferentially affect less massive globular clusters. Finally, the shapes of the projected GCS and dark matter halo distributions scale with each other, concluding that GCSs are effective tracers of the dark matter distribution in their host galaxies.