Merger rate density evolution of BBHs (upper panel), BHNSs (central panel), and BNSs (lower panel) as a function of redshift. The red (blue) solid lines represent the merger rate density for mergers produced in the fiducial model NoCHEpreMS (CHElOpreMS), assuming a metallicity spread of σ_Z = 0.3. The blue and red shaded regions highlight the portions of the plot enclosed by the merger rate density evolution calculated with metallicity spreads of σ_Z = 0.1 and 0.7. The grey shaded region show the 90% credible interval for the merger rate density evolution with redshift (upper panel), and the local merger rate density (central and bottom panel) reported by Abbott et al. (2023).