CD4 and breast cancer: The findings of intravesical pembrolizumab-treated BBN tumor in mice (Figure 3) could be bridged to a median decrease of 41% in urine levels of granulocytes two weeks after a single intravesical dose of pembrolizumab in association with a significant median increase of 18% and 12% in CD4+ and CD8+ T cells, respectively of BC patients [17].