TIGIT and cancer: TIGIT expression is increased on CD8+ T cells in HIV-infection and in cancer21, 22 and co-blockade of TIGIT and the PD-1/PD-L1 pathway was recently shown to in part restore the proliferative capacity and/or cytokine production of CD8+ T cells in some HIV-infected subjects23 and cancer patients21, 22in vitro, making these pathways promising candidates for restoration of CD8+ T cell responses.