IL10 and cancer: α-PD-1 monoclonal antibodies reverse T cell exhaustion in cancer patients and restore anti-tumor potential of T cells (20) Further upstream, blocking IL-10 inhibits upregulation of PD-L1 and α-IL-10 decreases frequency of PD1+ cells (preliminary data from our group DOI: 10.1101/2021.02.26.432955) (23).