  Topological materials and topological phases have recently become a hot topic
in condensed matter physics. In this work, we report a topological nodal-line
semimetal InxTaSe2, in the presence of both charge density wave (CDW) and
superconductivity. In the x = 0.58 samples, the 2 * /3 commensurate CDW (CCDW)
and the 2 * 2 CCDW are observed below 116 K and 77 K, respectively. Consistent
with theoretical calculations, the spin-orbital coupling gives rise to two
two-fold-degenerate nodal rings (Weyl rings) connected by drumhead surface
states, confirmed by angle-resolved photoemission spectroscopy. Our results
suggest that the 2 * 2 CCDW ordering gaps out one Weyl ring in accordance with
the CDW band folding, while the other Weyl ring remains gapless with intact
surface states. In addition, superconductivity emerges at 0.91 K, with the
upper critical field deviating from the s-wave behavior at low temperature,
implying possibly unconventional superconductivity. Therefore, InxTaSe2
represents an interesting material system to study the interplay between CDW,
nontrivial band topology and superconductivity.
