You don't need VBA for this, just conditional formatting. Let's say
table 1 is A1:A100 and table 2 is B1:B50. Highlight all of table 1 (From
B1 to B50) and go to the conditional formatting dialogue. Change it from
cell based to formula based and enter the formula:

=COUNTIF($A$1:$A$100,B1)>0

Then choose what formatting you want.