CD8A and breast cancer: By utilizing three-dimensional imaging mass cytometry to analyze tumor tissue biopsies from breast cancer patients undergoing chemotherapy or a combination of chemotherapy and anti-PD-L1 immunotherapy at three different time points, Wang et al. revealed that the cell density and proportion of CD8+GZMB+ T cells interacting with cancer cells in the TME of patients responding to ICB treatment are significantly higher compared to non-responding patients [34].