  The Ce(Co,Rh,Ir)In$_5$ family of ``Ce-115'' materials hosts an abundance of
correlated electron behavior, including heavy-fermion physics, magnetism,
superconductivity and nematicity. The complicated behavior of these entangled
phenomena leads to a variety of exotic physical properties, which, despite the
seemingly simple crystal structure of these compounds, remain poorly
understood. It is generally accepted that the interplay between the itinerant
and local character of Ce-$4f$ electrons is the key to their exotic behavior.
Here, we report theoretical evidence that the Ce-115 materials are also
topological semi-metals, with Dirac fermions around well-separated nodes. Dirac
nodes in each compound are present on the $\Gamma-Z$ plane close to the Fermi
level. As the Dirac bands are derived from In-orbitals, they occur in all
family members irrespective of the transition metal (Co,Rh,Ir). We present the
expected Fermi-arc surface state patterns and show the close proximity of a
topological Lifshitz transition, which possibly explains the high field physics
of Ce-115 materials. Experimentally, we highlight the surprising similarity of
Ce(Co,Rh,Ir)In$_5$ in high magnetic fields, despite the distinctly different
states of the Ce-$4f$ electrons. These results raise questions about the role
Dirac fermions play in exotic transport behavior, and we propose this class of
materials as a prime candidate for unconventional topological
superconductivity.
