Forkheadbox protein 3 (Foxp3) was initially identified as a key transcription factor for Tregs that is also expressed in PDAC tumor cells (also known as cancer-Foxp3) and can upregulate the expression of C-C motif chemokine ligand 5 (CCL5) to recruit Treg cells into the tumor microenvironment [100]. Here, CCL5 is linked to cancer.