By default, Excel will show the data point values when you hover over on chart (e.g., series, point, value). If you want to hide them, please follow the steps below:
Step 1: Click the "File" Tab from the ribbon;
Step 2: Click "Options" from the left navigation menu;
Step 3: Click "Advanced" from the left navigation menu in the dialog box;
Step 4: Uncheck "Show data point values on hover" under the section of "Chart";
Step 5: Click "OK" at the bottom to apply the changes.