  Weyl nodes and Fermi arcs in type-II Weyl semimetals (WSMs) have led to lots
of exotic transport phenomena. Recently, Mo$_{0.25}$W$_{0.75}$Te$_{2}$ has been
established as a type-II WSM with Weyl points located near Fermi level, which
offers an opportunity to study its intriguing band structure by electrical
transport measurements. Here, by selecting a special sample with the thickness
gradient across two- (2D) and three-dimensional (3D) regime, we show strong
evidences that Mo$_{0.25}$W$_{0.75}$Te$_{2}$ is a type-II Weyl semimetal by
observing the following two dimensionality-dependent transport features: 1) A
chiral-anomaly-induced anisotropic magneto-conductivity enhancement,
proportional to the square of in-plane magnetic field (B$_{in}$$^{2}$); 2) An
additional quantum oscillation with thickness-dependent phase shift. Our
theoretical calculations show that the observed quantum oscillation originates
from a Weyl-orbit-like scenario due to the unique band structure of
Mo$_{0.25}$W$_{0.75}$Te$_{2}$. The in situ dimensionality-tuned transport
experiment offers a new strategy to search for type-II WSMs.
