CentOS public key installation

Please write your question in detail here.
(Example) I am making a ●● system with PHP (CakePHP).
The following error message occurred while implementing the ■■ function.

Error message
Import cannot be read even if the command for installing the public key is written as follows
Applicable source code
$sudo rpm --import/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
Error:/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7: Import reading failed (2).

-Create public and private keys using teraterm.
・ I wonder if the version of CentOS is different $sudo rpm --import/etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-8
I tried to change CentOS-7 to CentOS-8.

Supplemental information (FW/tool version etc.)

The CentOS version I am currently using is CentOS8.
I would like to install the package after this.
By the way, the OS I use is Windows