You use the * to indicate a "cross" in the tables statement
proc freq data=WORK.SYPHILIS;
tables RACE * sex_o;
run;
You can use () to compare multiple variables with one or more other groups of variables.
proc freq data=WORK.SYPHILIS;
tables (RACE othervar) * (sex_o somevar);
run;
would create tables for race*sex_o, race*somevar, othervar*sex_o and othervar*somevar.