It seems ildasm doesn’t support the pbd file generated by unity.
ilspy can do this,but why?
You mean pdb files in .net? The latest version of ildasm can support both dlls and pdb files. Checkout https://itsmycode.com/how-to-view-intermediate-language-in-c-sharp-using-ildasm-exe/ for how to view the source code using ildasm.