Find Substring Within Column - Excel
You can use COUNTIF with a wildcard, e.g. if "Bob" is in A1 then you can check whether that exists somewhere in B1:B10 with this formula
=COUNTIF(B1:B10,"*"&A1&"*")>0
that formula will return TRUE if A1 exists anywhere in B1:B10 - it's not case-sensitive