In conclusion, despite many interesting theoretical proposals, modifying chemical reactivity through collective light-matter coupling remains a challenging task. There are several ongoing efforts, both experimental and theoretical, that are focused on clarifying what photochemical reactions can be controlled through collective light-matter coupling and, in such cases, what mechanisms allow this to occur in spite of the minuscule coupling of individual molecules to the cavity. Regardless, the experimental and theoretical works up to this point have demonstrated the potential for many molecule photochemical reactions to be controlled through light-matter coupling and have set the stage for future works to modify photochemistry in the collective coupling regime.