This review gives an overview of the protective role of CD8 ⁺ T cells in SARS-CoV-2 infection. The cross-reactive responses intermediated by CD8 ⁺ T cells in unexposed cohorts are described. Additionally, the relevance of resident CD8 ⁺ T cells in the upper and lower airway during infection and CD8 ⁺ T-cell responses following vaccination are discussed, including recent worrisome breakthrough infections and variants of concerns (VOCs). Lastly, we explain the correlation between CD8 ⁺ T cells and COVID-19 severity. This review aids in a deeper comprehension of the association between CD8 ⁺ T cells and SARS-CoV-2 and broadens a vision for future exploration.