  The quest for quantum materials with diverse symmetry-protected topological
states has been the focus of recent research interest, primarily due to their
fascinating physical properties and the potential technological utility. In
this work, we report on the magnetotransport, de Haas-van Alphen (dHvA)
oscillations, and the first-principles calculations of the stannide Cu$_3$Sn
that is isostructural with the recently reported topological semimetal
Ag$_3$Sn. The magnetoresistance was found to vary quasi-linearly in field.
Clear dHvA oscillations were observed under a field as low as 1 Tesla at 2 K,
with three major oscillation frequencies $F_{\alpha}$=8.74 T,
$F_{\beta}$=150.19 T and $F_{\gamma}$=229.66 T and extremely small effective
masses. The analysis of dHvA quantum oscillations revealed a possible nonzero
Berry phase, suggestive of the nontrivial band topology. The corroborating
evidence for the nontrivial electronic topology also comes from the
first-principles calculations which yield a nonzero $\mathbb{Z}_2$ topological
index. These results collectively suggest that Cu$_3$Sn, in analogy to its
homologue Ag$_3$Sn, may be another intermetallic stannide hosting topological
Dirac fermions.
