Summary of CKM 2016 Working Group 4 : mixing and mixing-related $CP$ violation in the $B$ system

We summarize the new results on $B$ meson mixing and mixing-related $CP$ violation presented at CKM2016. We place these results in the context of both previous experimental measurements and the most recent theoretical developments in the field, and discuss prospects for ongoing and future mixing and mixing-related $CP$ violation measurements.