Your macOS is blocking the file because it was downloaded from the internet or created by an unrecognized source.

For this file only, use the Context Menu to Open:

1. Right-click (or Control-click) on the file.
2. Select Open from the context menu. This may prompt a message asking if you're sure you want to open it. Confirm that you do.

For all files (in case you decide to go this way in the future),

1. Go to System Preferences > Security & Privacy.
2. In the General tab, check for a message saying the file was blocked. If so, you may see an option to allow it.
3. Click Allow Anyway to permit the file to open.