  In transition metal compounds, due to the interplay of charge, spin, lattice
and orbital degrees of freedom, many intertwined orders exist with close
energies. One of the commonly observed states is the so-called nematic electron
state, which breaks the in-plane rotational symmetry. This nematic state
appears in cuprates, iron-based superconductor, etc. Nematicity may coexist,
affect, cooperate or compete with other orders. Here we show the anisotropic
in-plane electronic state and superconductivity in a recently discovered kagome
metal CsV$_3$Sb$_5$ by measuring $c$-axis resistivity with the in-plane
rotation of magnetic field. We observe a twofold symmetry of superconductivity
in the superconducting state and a unique in-plane nematic electronic state in
normal state when rotating the in-plane magnetic field. Interestingly these two
orders are orthogonal to each other in terms of the field direction of the
minimum resistivity. Our results shed new light in understanding non-trivial
physical properties of CsV$_3$Sb$_5$.
