Early reports produced concerns about lack of efficacy and possible detrimental effects of anti PD-1 therapy in PTCL, such as hyper progression [66,67]; however, the relative number of PTCL_NOS patients enrolled in these trials was too small to draw any definite conclusion for this specific PTCL subtype. Here, PDCD1 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.