Identification of jets originating from b or c quarks is important for a wide variety of standard model physics (e.g. final states involving top quarks and Higgs bosons) as well as searches for physics beyond the standard model. Due to the increased center-of-mass energy during the LHC Run 2, final states with boosted b quark jets became increasingly important.

The CMS Collaboration improved on the existing b jet identification algorithms, and developed the first charm jet tagger. To address boosted topologies a boosted double-b tagger has been developed as well.
A review of these new developments is presented, together with their performance on proton-proton collision data recorded by the CMS detector at a centre-of-mass energy of $\sqrt{s} = 13$ TeV during 2015 and 2016.