We found that Rap1b expression had a close link with T lymphocyte-related immune genes (CD80, CD86, CD28), neutrophil associated immune genes (CD44) and cancer-related genes, such as neuropilin-1 (NRP1), endothelial low-affinity A2b adenosine receptor (ADORA2A) and programmed cell death 1 ligand 2 (PDCD1LG2) in different kinds of tumors. This evidence concerns the gene PDCD1LG2 and cancer.