We are expecting high-precision observations from upcoming CMB surveys, such as the Simons Observatory, CMB-S4, and LiteBIRD, as well as from future surveys of the large-scale structure, such as Euclid, Rubin LSST, SPHEREx, PSF, and Roman Space Telescope. Most of the observables from these independent surveys will be correlated due to their large overlaps in sky and redshift coverage. Joint analysis of CMB and LSS surveys will allow us to increase the overall signal, break degeneracies, mitigate systematics, and potentially probe new science. In this talk, I will discuss the possible paths to simulate correlated CMB and LSS observables to achieve these scientific goals.