CXCR4 and nonpapillary renal cell carcinoma: In addition to the clinical efficacy demonstrated by the combination of tyrosine kinase inhibitors, the oral CXCR4 inhibitor mavorixafor combined with nivolumab has shown potential antitumor activity in clinical trials for metastatic ccRCC patients who did not respond to nivolumab monotherapy, particularly in patients with stable disease [113].