In comparison to the untreated control group, tumors treated with checkpoint inhibitors demonstrated more adoptive T-cell infiltration at the invasive margins at the junction between the collagen fibers detected with second harmonic generation, and the mCherry-labeled tumors, as well as the upregulation of CD44, an adhesion marker which mediates T-cell migration into the tumor interstitium (41). Here, CD44 is linked to neoplasm.