Excel: Multiple Nested IF

I have the following issue:

=CONCATENATE(IF(W7=0, "Today", ""), IF(W7=1, "Tomorrow", ""), IF(W6="Completed", "Completed", ""), IF(W7<=-1, "Late ", ""))

Now, if W7 is 0,1 or <=-1 my output column will show Today, Tomorrow or Late. and if W6 says completed it will show completed.

Issue: Now is W7 says 0 and W6 says completed, it says "TodayCompleted" However what I am looking for is that if it says completed, it takes priority and it will ignore the W7 value. Meaning, if W6 is completed, it will ignore anything inside the W7 and just say completed. If W6 is empty, it will show the W7 value.

I would love to have help on this and sincerely appreciate anyone who could shed some light on this using a formula, or even better with conditional formatting.

Thanks and best regards