To unhide a column that was hidden, please refer to Ctrl+Shit+0 if you like using shortcut to unhide a column or follow the steps below for commands:
Step 1: Select columns between the hidden column;
Step 2: Right-click and select "Unhide" from the dialog box;
Step 3: The hidden column will show up.
Alternatively, please use the commands in the ribbon.
Step 1: Select the hidden columns between the column;
Step 2: Click the "Home" tab from the ribbon;
Step 3: Click "Format" in the Cells section, and select "Unhide Columns" from the "Hide & Unhide" command;
Step 4: The hidden column will appear.