Search Values from a List(Query 1), in a Text string(Query 2A), and return those Values(Query 2B)

Hi singhv2,

You can write a calculated column on table 2 to check all keys and combine matched items.

Result = 
CONCATENATEX (
    FILTER (
        ALL ( 'Key Information' ),
        SEARCH ( [Key], [PO Line Description], 1, -1 ) > 0
    ),
    [Key],
    ","
)

Regards,

Xiaoxin Sheng