FOXP3 and nonpapillary renal cell carcinoma: (3) Among the three ICIs tested, the combination treatment of shikonin with ipilimumab confirmed a significantly decrease of the frequency of CD4+ CD25+ CD127low/- FOXP3+ Treg in PBMC of ccRCC patients as well as an enhancement of the CD3+CD4+ T cells, compared to the group without treatment.