To address which immune subsets are involved in CCL5 signaling in pancreatic cancer, we developed a 17-color spectral flow cytometry panel to monitor the tumor-infiltrating immune microenvironment in parallel (Figure 2—figure supplement 1C) and employed a specific CCR5i (maraviroc), to block CCR5, the most widespread and highest-affinity receptor for CCL5 expressed on Tregs (Figure 1—figure supplement 1A). Here, CCR5 is linked to familial pancreatic carcinoma.