It was found that XCR1 and CXCL9 have a significant positive correlation in a variety of tumors, including THCA, SKCM, SARC, KIRC, TGCT, BRCA, PCPG (pheochromocytoma and paraganglioma), and KIRP (Figure 5C). Here, CXCL9 is linked to hereditary pheochromocytoma-paraganglioma.