  The recent discovery of a nonsaturating linear magnetoresistance in several
correlated electron systems near a quantum critical point has revealed an
interesting interplay between the linear magnetoresistance and the zero-field
linear-in-temperature resistivity. These studies suggest a possible role of
quantum criticality on the observed linear magnetoresistance. Here, we report
our discovery of a nonsaturating, linear magnetoresistance in Mo$_8$Ga$_{41}$,
a nearly isotropic strong electron-phonon coupling superconductor with a
linear-in-temperature resistivity from the transition temperature to $\sim$55
K. The growth of the resistivity in field is comparable to that in temperature,
provided that both quantities are measured in the energy unit. Our datasets are
remarkably similar to magnetoresistance data of the optimally doped
La$_{2-x}$Sr$_x$CuO$_4$, despite the clearly different crystal and electronic
structures, and the apparent absence of quantum critical physics in
Mo$_8$Ga$_{41}$. A new empirical scaling formula is developed, which is able to
capture the key features of the low-temperature magnetoresistance data of
Mo$_8$Ga$_{41}$, as well as the data of La$_{2-x}$Sr$_x$CuO$_4$.
