T cells play a crucial role in controlling SARS-CoV-2 infections. The hypermutated BA.2.86 variant, which emerged in July 2023, exhibits numerous mutations in the spike protein, potentially enhancing its immune evasion capabilities. Müller et al. investigated whether memory T cells can effectively recognize these mutated epitopes in healthy individuals and patients with chronic lymphocytic leukemia (CLL). They found that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells, induced by prior infection or vaccination, demonstrated robust immune recognition of BA.2.86. Both T cell magnitudes and functional capacities, including cytokine expression and proliferative responses, were largely preserved against mutated spike epitopes of BA.2.86. These findings suggest that memory T cells continue to provide cell-mediated immune protection against highly mutated variants like BA.2.86, highlighting the importance of T cell responses in controlling SARS-CoV-2 infections.T cells play a crucial role in controlling SARS-CoV-2 infections. The hypermutated BA.2.86 variant, which emerged in July 2023, exhibits numerous mutations in the spike protein, potentially enhancing its immune evasion capabilities. Müller et al. investigated whether memory T cells can effectively recognize these mutated epitopes in healthy individuals and patients with chronic lymphocytic leukemia (CLL). They found that SARS-CoV-2 spike-specific CD4+ and CD8+ T cells, induced by prior infection or vaccination, demonstrated robust immune recognition of BA.2.86. Both T cell magnitudes and functional capacities, including cytokine expression and proliferative responses, were largely preserved against mutated spike epitopes of BA.2.86. These findings suggest that memory T cells continue to provide cell-mediated immune protection against highly mutated variants like BA.2.86, highlighting the importance of T cell responses in controlling SARS-CoV-2 infections.