The top-quark pair production in association with heavy-flavour jets (b- or c-jets) is a difficult process to calculate and model and is one of the leading sources of background to Standard Model
measurements of ttH and four-top production in final states with one or two leptons. To improve our understanding of these processes, tt+bb inclusive and differential cross-section measurements were performed by the ATLAS and CMS Collaborations, and an inclusive tt+cc cross-section measurement was performed by the CMS Collaboration.