CXCL9 and ovarian carcinoma: In human ovarian cancer, myeloid cells have a dual role: while they favor immunosuppressive microenvironment by TGFβ production, regulatory T cells recruitment and PD-L1 expression (33–35), these cells also provide CD28 costimulation, which is required for reinvigoration of CD8+ TILs and for their response to PD-1 blockade, and are the main source of CXCL9, which is essential for T-cell recruitment (36, 37).