The Higgs boson discovered at the LHC may be part of a larger scalar sector, as various properties of this new particle still remain to be measured. Searches for additional light bosons provide a powerful way to probe extensions of the Standard Model, particularly through direct measurements of Higgs boson exotic decay branching fractions. In this seminar, I will present two such searches with the CMS experiment targeting final states with tau leptons and b quarks, and discuss how they form part of a broader program to characterize the Higgs boson. I will conclude with the current status of Higgs boson exotic decay searches and prospects for Run 3.