Yes, you can link a text box in PowerPoint to a cell in Excel. Here are the steps to do it:

1. Open both PowerPoint and Excel.
2. In Excel, select the cell that you want to link to the text box in PowerPoint.
3. Press Ctrl+C to copy the cell.
4. In PowerPoint, select the text box that you want to link to the Excel cell.
5. Click on the "Insert" tab in the ribbon.
6. Click on the "Text Box" button and draw a text box on the slide.
7. Click inside the text box and paste the copied cell by pressing Ctrl+V.
8. The text box should now display the value of the linked cell in Excel.
9. To update the value in the text box, simply change the value in the linked cell in Excel and the text box in PowerPoint will update automatically.

Note: When you link a text box to an Excel cell, the text box will only display the value of the cell, not the formula. If you want to display the formula, you will need to use a different method.