CXCR4 and cancer: Reports, however, of TLSs in PDAC (2–4), of neoantigens with homology to infectious disease-derived peptides in long-term survivors of PDAC (6), and signs of improved anti-PDAC immunity in metastatic lesions of patients with PDAC after inhibition of CXCR4 (5) all point to a need for a deeper understanding of the relationship between this cancer and the immune system.