The shortcut Ctrl+Shift+7 is to apply an outline border to the selected cells. Please also refer to the shortcut Ctrl+Shift+Ampersand (&).
Step 1: Select the data range you want to add the outline border;
Step 2: Press the "Ctrl" and "Shift" keys from the keyboard, then press the number 7 from the keyboard in the alphanumeric area.
