BBH merger rate computed in the cosmological zoom-in simulations m11e, m11d, and m12i from top to bottom by sampling massive star clusters from individual GMCs and integrating them forward in time with the code CMC (red, see Paper III), and from the results of our cluster sampling algorithms (models ‘Gamma’, ‘EB18’, and ‘SFRpeak’ respectively presented from left to right) combined with predictions of the 3D grid. For each model, the process is repeated 100 times and we show the mean BBH merger rate (black solid line) as well as the 90% credible interval (grey shaded area).