Groundbreaking research has revealed that common respiratory viruses, including SARS-CoV-2 and influenza, can reactivate dormant breast cancer cells in the lungs, potentially triggering metastasis. Using mouse models, researchers demonstrated that viral-induced inflammation prompts dormant cells to express markers and genes associated with active metastasis. Mechanistically, the inflammatory cytokine interleukin-6 (IL-6) was implicated in early activation stages, with T-cell populations influencing sustained cancer cell activation. These findings provide novel insights into cancer relapse mechanisms and highlight viral infections as a significant factor in metastatic disease progression.