How to link a cell to a different sheet in Google Sheets?

For this, you can Use IMPORTRANGE

Imports a range of cells from a specified spreadsheet.

Sample Usage

IMPORTRANGE("https://docs.google.com/spreadsheets/d/abcd123abcd123", "sheet1!A1:C10")

IMPORTRANGE(A2,"B2")

Syntax

IMPORTRANGE(spreadsheet_url, range_string)

• spreadsheet_url - The URL of the spreadsheet from where data will be imported. The value for spreadsheet_url must either be enclosed in quotation marks or be a reference to a cell containing the URL of a spreadsheet.
• range_string - A string, of the format "[sheet_name!]range" (e.g. "Sheet1!A2:B6" or "A2:B6") specifying the range to import. The sheet_name component of range_string is optional; by default IMPORTRANGE will import from the given range of the first sheet. The value for range_string must either be enclosed in quotation marks or be a reference to a cell containing the appropriate text.

Notes

• Spreadsheets must be explicitly granted permission to pull data from other spreadsheets using IMPORTRANGE. The first time the destination sheet pulls data from a new source sheet, the user will be prompted to grant permission. Once access is granted, any editor on the destination spreadsheet can use IMPORTRANGE to pull from any part of the source spreadsheet. The access remains in effect until the user who granted access is removed from the source.
• If the data you are trying to import is too large, you may get an error.