The genetic basis for lineage-specific traits is often encoded in gene regulatory sequences. This might be particularly true for important, pleiotropic genes, which are involved in many different processes and cannot tolerate mutations in their protein-coding sequences. Instead, changes to their regulatory elements can lead to expression in new cell types and time points, allowing evolutionary change to happen while the protein function remains unperturbed. We strive to identify mechanisms and processes of gene regulatory evolution across diverse mammals. We use computational approaches to compare the genomes of hundreds of mammals and identify sequences undergoing lineage-specific evolution. We integrate this with functional genomics experiments in stem cell-derived model systems to further explore gene regulatory evolution across diverse mammals.