Sunyaev-Zeldovich (top) and X-ray (bottom) scaling relations versus halo mass (M_500c) in TNG-Cluster, and comparison to selected data. Top: the Y_SZ, 500 − M_500c relation of the simulated clusters is relatively tight and has a slope consistent with the 5/3 self-similar expectation. We compare to large survey SZ data from Planck (Planck Collaboration XX 2014; Hill et al. 2018), weak-lensing based cluster mass estimates (Nagarajan et al. 2019), and early NIKA2 observations (Adam et al. 2024). Bottom: the integrated 0.5 − 2 keV cluster luminosity within R_500c rises as a function of mass, and with significant scatter. We compare to available X-ray samples at low redshift (Pratt et al. 2009; Vikhlinin et al. 2009; Mantz et al. 2016; Bulbul et al. 2019; Lovisari et al. 2020). The SZ and X-ray scaling relations are both in broad qualitative agreement with data.