Google Sheets' query + IFS function

I want to use IFS and Query in google sheet at the same time.

Works Well

=QUERY('PN Orders'!A1:AF,"SELECT C, D where C LIKE '%" & $B$1& "%' and D LIKE '%" & $B$2& "%' LIMIT " &$B$3,1)

above query works well, get results. But every time I combine it with IFS function, it returns nothing.

Doesn't work

=ifs( and($B$1<>"",$B$2<>"")=true, QUERY('PN Orders'!A1:AF,"SELECT C, D where C LIKE '%" & $B$1& "%' and D LIKE '%" & $B$2& "%' LIMIT " &$B$3,1))

Is there something I'm missing here?
Why the query returns nothing when combined with IFS function?