Yes, now Hive supports IN or EXIST, operators. Also, you can use left semi join here. Left Semi Join performs the same operation IN do in SQL.
So if you have the below query in SQL-
SELECT a.key, a.value
WHERE a.key in
Then the suitable query for the same in Hive can be-
SELECT a.key, a.val
FROM a LEFT SEMI JOIN b on (a.key = b.key)
Both will fulfill the same purpose.