  Trilayer graphene {(TLG)} consists of three layers of graphene arranged in a
particular stacking order. In the case of ABC-ABA-ABC stacking, the layers are
arranged in an A-B-C sequence, followed by an A-B-A sequence, and again an
A-B-C sequence. This stacking arrangement introduces specific electronic
properties and band structures due to the different stacking configurations. We
focus on elucidating the transport properties of a p-n-p junction formed with
ABC-ABA-ABC stacking TLG. Employing the transfer matrix method and considering
continuity conditions at the junction boundaries, we establish transmission and
reflection probabilities, along with conductance. Notably, electron transport
through the ABC-ABA-ABC junction exhibits Klein tunneling, resulting in
substantial conductance even in the absence of a potential barrier $V_0$. This
effect arises from the effective barrier induced by our specific stacking,
facilitating the passage of a maximal number of electrons. However, the
presence of $V_0$ diminishes Klein tunneling, leading to conductance minima.
Furthermore, our findings highlight that interlayer bias $\delta$ induces a
hybridization of the linear and parabolic bands of ABA-TLG within the junction,
reducing resonances. In cases where $\delta\neq0$ and $V_0\neq0$, we observe a
suppression of the gap, contrary to the results obtained in ABC tunneling
studies where a gap exists.
