PDCD1 and neoplasm: They can also express PD1, which may act as a tumor suppressor on malignant T cells.1 Thus, in principle, blocking the PD1/PDL1 synapse in PTCL may lead to either tumor regression or progression.2 Nevertheless, PD1-blockade demonstrated antitumor activity in monotherapy in patients with relapsed/refractory (R/R) PTCL with an ORR around 33%.3,4