CD40 and viral infectious disease: Among the sICs, CD27 and CD40, which were identified as factors with high prognostic power through ML analysis in this study, play important roles in promoting the survival and effector functions of natural killer/T cells in viral infection, IFN-I response, and inhibition of its signaling (Yao et al., 2016; Bullock, 2017; Remedios et al., 2019; Deng et al., 2021).