To understand the .pkg , you have to understand the anxiety of 2015.
Technical Deployment Report: Microsoft Office 2016 Installer (macOS) Executive Summary microsoft-office-2016-installer.pkg
You likely have macOS 10.15 (Catalina) or newer. Office 2016 requires the 32‑bit to 64‑bit transition. The final compatible version is macOS 10.14 Mojave. To understand the