ICOS and peripheral T-cell lymphoma, not otherwise specified: Importantly, the established SS PDX model exhibited a stable immunophenotype and expressed several cell surface targets (ICOS, PD-1, TRBC1 and KIR3DL2) that are currently the subject of early clinical investigation in peripheral T-cell lymphoma (Chavez et al., 2023; Khodadoust et al., 2020; Maciocia et al., 2017; Marie-Cardine et al., 2014).