Hello,

Since our schedule is shared on the sharepoint, my boss wants me to ensure that the certain original dates should not be edited by anyone. And also, some sensitive data should be viewed only by small teams.
Is there a way where I could make certain columns as read only or blacked them out?

Thanks in advance

By the way, I googled out a solution called SharePoint Column View Permission, which offers a great solution to do that. However, it is a third party tool.
It will be great if I can get some other solutions like code.
Thanks!

Excel's built-in protection tools, I imagine. Is ANYONE supposed to be editing your spreadsheet in any way? Or is it just up there as a reference took for people to look at?

If it's just there as a reference, then don't put the spreadsheet on the SharePoint, put a PDF copy of your spreadsheet. Nobody can edit THAT!