ICIs, notably PD-1 inhibitors (e.g. nivolumab, pembrolizumab) and CTLA-4 inhibitor ipilimumab, are now standard in some hematologic contexts (for example, PD-1 blockers in relapsed/refractory Hodgkin lymphoma) and are being investigated in others. Here, PDCD1 is linked to Hodgkins lymphoma.