PDCD1 and inclusion body myositis: Knauss et al. provided evidence of the activation of the PD-1 pathway and the presence of dysfunctional T cells in some inflammatory myopathies, such as immune-mediated necrotizing myopathy (IMNM), sporadic inclusion body myositis (sIBM), and also in irMyositis (Knauss et al., 2019).