  Unveiling the nature of progenitors is crucial for understanding the origin
and the mechanism of core-collapse and thermonuclear supernovae (SNe). While
several methods have been developed to derive stellar properties so far, many
questions remain poorly understood. In this paper we demonstrate an
observational approach to constrain progenitors of supernova remnants (SNRs)
using abundances of carbon (C), nitrogen (N), and oxygen (O) in shock-heated
circumstellar material (CSM). Our calculations with stellar evolution codes
indicate that a total amount of these CNO elements will provide a more
sensitive determination of the progenitor masses than the conventional method
based on ejecta abundances. If the CNO lines (particularly those of C and N)
are detected and measured their abundance ratios accurately, they can provide
relatively robust constraint on the progenitor mass (and in some cases the
rotation velocity) of SNRs. Since our method requires a better energy
resolution and larger effective area in the soft X-ray band ($<1$~keV), XRISM
launched on September 7, 2023 and next-generation microcalorimeter missions
such as Athena, Lynx, LEM, and HUBS will bring a new insight into link between
the progenitors and their remnants.
