Exploring elementary particles and their interactions is an age-old endeavour of humanity. With the 27 km circumference Large Hadron Collider (LHC) at CERN and the monumental detectors around it, scientists from all over the world have access to the most advanced tools to continue this exploration. A major achievement was the experimental confirmation of the existence of the Higgs boson particle in 2012, some 50 years after it had been predicted by Robert Brout, François Englert, and Peter Higgs. Fundamental questions about the reality around us, however, remain, such as, e.g., the nature of dark matter, the matter-antimatter asymmetry, the weakness of gravity, and the unification of all forces. The Compact Muon Solenoid (CMS) detector, to which the Flemish particle physics groups contributed in the design, construction, maintenance, and operation since its conception in the 1990’s, allows to investigate and test many theoretical ideas that are being proposed to answer these questions. This project is vital to pursue this participation so that our groups can collect and analyse “Run 3” data and prepare the CMS detector for the upgraded High-Luminosity LHC.