Left: 0.5 − 2 keV MOS1 CGM luminosity of the cE galaxies with detected X-ray emission within r_vir as a function of their stellar mass. The shaded region shows the best-fit relation and its 1σ uncertainty from Zhang et al. (2024). Right: Virial mass of cEs calculated from the 0.5 − 2 keV CGM luminosity as a function of stellar mass. The shaded region shows the best-fit relation at z = 0 with its 1σ confidence interval from Behroozi et al. (2019). Overall, based on X-ray measurements, the cEs largely follow both the M_★ − L_X and the M_★ − M_vir relations established for the local galaxy population, however, their virial mass is on the lower side of expectations, possibly hinting at a more compact halo structure.