Explanation
This formula uses the TEXT function to concatenate the month and year of each date.
Then, the two dates are tested for equality.
Use other cells for input
You don’t need to hard-code a date into the rule.
To make a more flexible rule, it’s possible for you to use another cells like a variable.
This simplifies the formula and makes it easier to read.
Other formulas
There are several other formulas you could use to solve this problem.
TEXT Function
The Excel TEXT function returns a number formatted as text.
in a text string with the number format of your choice.