In particular, in many types of cancer, hypoxia does not affect or decrease the expression of CCL2/MCP-1, CCL7/MCP-3, CCL5/RANTES, CCL3/MIP-1α, CCL4/MIP-1β CCL17/TARC, CCL22/MDC, CCL19/ELC, CCL21/SLC, CCL27/ESkine, and CCL28/MEC—chemokines that are relevant for the infiltration of tumors by cytotoxic and anticancer TIL [49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76]. This evidence concerns the gene CCL21 and cancer.