  Kane fermion is the counterpart of the Dirac fermion with pseudospin-1. Due
to the existence of a bunch of gapless modes associated with Landau levels, the
magnetic transport property of Kane fermion gas is very different from that of
the Dirac semimetal. We calculate the magneto-optical conductance of the Kane
fermion gas. We find that these gapless modes will contribute to a series of
resonant peaks in low frequencies. We find that these peaks can explain the low
frequency absorbance spectrum in a recent experiment for the Kane fermion
material Hg$_{1-x}$Cd$_x$Te.
