Suppose you are given a date and you are asked to calculate next working day if date is of weekend. If date is a regular workday, then you should show the same date.

For example - 8-Mar-19 is a working day. Hence, you should show the same date. But if this is either 9-Mar-19 or 10-Mar-19 which are Saturday and Sunday, then you must show 11-Mar-19 as the next workday.

In this case, formula to be used would be

=WORKDAY(A2-1,1)

Assuming, your holidays are in E2:E3, then formula would be

=WORKDAY(A2-1,1,$E$2:$E$3)