GENERATE Returns a table with the Cartesian product between each row in table1 and the table that results from evaluating table2 in the context of the current row from table1.
Syntax
GENERATE(table1, table2)
Parameters
table1 – Any DAX expression that returns a table.
Table2 – Any DAX expression that returns a table.
Return Value
A table with the Cartesian product between each row in table1 and the table that results from evaluating table2 in the context of the current row from table1
Reference Data
https://docs.microsoft.com/en-us/dax/dax-function-reference