After establishing a relationship between the tables, you can use the RELATED function to access the data from the related table.
SWITCH (
[Column1],
"Value1", RELATED(Table2[Column2]),
"Value2", RELATED(Table2[Column3]),
"Other"
)
RELATED function works by following the relationships that you have defined in your data model. If there isn't a direct relationship between the tables, you may need to create one or modify your data model to support the calculations you're trying to perform.