Thus far, studies employing classical rate theories or ringpolymer molecular dynamics simulations have struggled to accurately capture shape of the resonance observed in the cavity frequency-dependent rate profile. On the other hand, quantum dynamics simulations, performed in the singlemolecule and few-molecule limit, have demonstrated the ability to depict the correct resonance structure. Yet, the questions remain as to why classical approaches fall short, and to what extent quantum effects are involved in this resonant modification of the reaction rate inside the optical cavity.