Although there has been significant progress in deciphering the genomic landscape of the many diseases entailed in the term PTCL, little is known about the mechanisms that underlie the effects of anti-PD-1 ICIs in T-cell-derived tumors, and alarming signals have been associated with their use in certain subtypes. Here, PDCD1 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.