  This study reports \textit{CP} asymmetry measurements in charmless three-body
decays of \textit{B} mesons, both using the Run II data from proton-proton
collisions at a center-of-mass energy of 13 $TeV$, collected by the LHCb
detector from 2015 to 2018, with an integrated luminosity of 5.9 $fb^{-1}$.
Significant \textit{CP} asymmetries are observed in $B^\pm \rightarrow \pi^\pm
\pi^+ \pi^- $ and $B^\pm \rightarrow K^\pm K^+ K^- $ decays, while the
previously observed asymmetry in $B^\pm \rightarrow \pi^\pm K^+ K^- $ decays is
confirmed, and the \textit{CP} asymmetry of $B^\pm \rightarrow K^\pm \pi^+
\pi^- $ decays is found to be compatible with zero. Additionally, a new method
is used to measure the \textit{CP} asymmetry in charmless $B \rightarrow PV$
decays, showing significant asymmetry in $B^\pm \rightarrow K^\pm \pi^+ \pi^- $
decays dominated by $\rho(770)$, representing the first observation of
\textit{CP} violation in this process. Other decay channels show \textit{CP}
asymmetries compatible with zero.
