QCD NLO corrections to $t\bar{t}Z$ production at the LHC including leptonic decays

The calculation of $t\bar{t}Z$ production including leptonic decays of both $Z$ boson and top quarks via a partially or fully off-shell calculation represents a definite step forward towards a more accurate description of events whose signatures originate from $t\bar{t}Z$ production. In this talk we review two studies that represent the state of the art of theoretical modeling of $t\bar{t}Z$ production by either performing the NLO QCD calculation of the fully decayed $pp\to e^{+}{\nu }_e{\mu }^{-}{\bar{\nu }}_{\mu }b\bar{b}{\tau }^{+}{\tau }^{-}$ process (see Ref. [1]) or matching the NLO QCD calculation of $pp\to t\bar{t}{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ to parton shower, including top-quark decays with approximate LO spin correlation (see Ref.[2]).