In the list of capabilities, I found there's both
delete_users. It's not clear to me what
remove_users is supposed to do, the Codex documentation just says it was introduced in version 3.0 (https://codex.wordpress.org/Roles_and_Capabilities).
The difference is really no difference in regular (single install) WordPress. It's in a multisite install (network) where there is a difference.
In multisite, only a Super Admin (who can manage everything on the network) has
delete_users capability, while an "admin" (who would own/manage a single site) can
remove_users from their site, but cannot delete them from the network.
Hope that helps clarify.