A zero trust platform means that (in theory), we'd be able to run malicious code inside our platform with no risk – the code wouldn't be able to interact with anything dangerous without being granted special access by the platform's own security/infrastructure team.
The idea is that we don't want to trust just anything simply because it's inside our platform. Instead, we want individual services to be trusted based on a short and deliberate list of which other services they're allowed to interact with. This makes an attack substantially more difficult.