Getting a value from a second table by filtering from the first table

umutkaya79 , Try like

Margin =
VAR SelectedGroup = values('Exposure - All'[exposure_analysis_group])
RETURN
CALCULATE(
MAX('tbExtractFMTenant'[trend_query_margin]),
FILTER('tbExtractFMTenant', 'tbExtractFMTenant'[tenant_name] in  SelectedGroup)
)

of exploring treatas

https://docs.microsoft.com/en-us/dax/treatas-function

https://www.sqlbi.com/articles/propagate-filters-using-treatas-in-dax/