In my ~/.cshrc, it is like:

set arc_prompt="%{\e[36m%}[%C3]%{\e[0m%} %{\e[35m%}%g%v%{\e[0m%}%# "

But after I added at the end of .cshrc:
zoxide init tcsh > ~/.zoxide.tcsh
source ~/.zoxide.tcsh

it could be like:

I don't want to change my prompt. Is it possible?

A workround I found is that, in .cshrc:

set arc_prompt="%{\e[36m%}[%C3]%{\e[0m%} %{\e[35m%}%g%v%{\e[0m%}%# "
zoxide init tcsh > ~/.zoxide.tcsh
alias sz 'source ~/.zoxide.tcsh'

After I already get my prompt, I execute "sz". In this case, I can keep my old prompt and make "z" still work. I don't quite understand why...