  Besides the negative longitudinal magnetoresistance (MR), planar Hall effect
(PHE) is a newly emerging experimental tool to test the chiral anomaly or
nontrivial Berry curvature in Weyl semimetals (WSMs). However, the origins of
PHE in various systems are not fully distinguished and understood. Here we
perform a systematic study on the PHE and anisotropic MR (AMR) of Td-MoTe2, a
type-II WSM. Although the PHE and AMR curves can be well fitted by the
theoretical formulas, we demonstrate that the anisotropic resistivity arises
from the orbital MR (OMR), instead of the negative MR as expected in the chiral
anomaly effect. In contrast, the absence of negative MR indicates that the
large OMR dominates over the chiral anomaly effect. This explains why it is
difficult to measure negative MR in type-II WSMs. We argue that the measured
PHE can be related with the chiral anomaly only when the negative MR is
simultaneously observed.
