Low programmed death-ligand 2 (PD-L2) was the most sensitive/specific marker to segregate patients with adverse outcomes; therefore, PD-L2 expression was chosen to distinguish immune infiltration<sup>HI</sup> (ie, high PD-L2) FL biopsies from immune infiltration<sup>LO</sup> (ie, low PD-L2) tumors.
Thus, PD-L1 and PD-L2 are interesting targets for peptide vaccines in diseases where the tumor microenvironment is known to play an essential role such as multiple myeloma and follicular lymphoma.