Yes, you can absolutely combine conditional formatting with data validation rules in Excel to create a more dynamic and informative spreadsheet. Here's how:

Scenario: Imagine you have a dropdown list in cell A1 with options like "High", "Medium", and "Low". You want to highlight cells in column B based on the selection in the dropdown.

1. Set up Data Validation:
- Select cell A1.
- Go to the "Data" tab and click "Data Validation" in the "Data Tools" group.
- Choose "List" under "Allow" and define your options (e.g., "High,Medium,Low").

2. Conditional Formatting based on Data Validation:
- Select the cells in column B (where you want formatting to change).
- Go to the "Home" tab and click "Conditional Formatting" in the Styles group.
- Choose "New Rule..."

3. Use a formula to determine formatting:
- Select "Use a formula to determine which cells to format."
- In the formula box, enter a formula that references the data validation cell (A1) and compares it to your desired criteria. For example:

- To highlight cells with "High" selected: `=A1="High"`
- To highlight cells with "Medium" or "Low" selected: `OR(A1="Medium",A1="Low")` (OR function checks multiple conditions)

4. Set Formatting:
- Click the "Format" button and choose the formatting you want to apply when the condition is met (e.g., background color).
- Click "OK" on both the formatting and rule creation windows.

Now, when you change the selection in the dropdown (cell A1), the conditional formatting will automatically update the formatting in column B based on the chosen option. This allows for a clear visual representation of the data based on the user's selection through data validation.