A phase Ib clinical trial including 66 patients with different types of malignancies (including TNBC) showed that navoximod combined with atezolizumab upregulated the expression of IDO and PD-L1 on the surface of all types of tumor cells leading to partial remission in 9% of patients and stable disease in 17%, while PD-L1+ patients had a slightly higher response rate than PD-L1− patients [186]. This evidence concerns the gene IDO1 and neoplasm.