sentence: Immunotherapy for microsatellite stable CRC or pancreatic cancer has been so far futile.5 45 46 Previous data from animal experiments indicated a beneficial effect of inhibition of the SDF1alpha / CXCL12 receptor CXCR4.27 29 The described changes included attraction of T cells into the microenvironment and subsequent activation via anti-PD-1 to induce massive tumor regression .