...but it is not the headline.
Over time, many slide decks becomes so cluttered and messy that I have seen people adding a sentence or a bubble on each slide with a sentence that summarises the message of the slide. (I have even seen them in the footnotes on every page). "What we really want to say is this".
Why do this last, instead of first? If you start with the sentence, and you build your slide just to support that message, the slide will be a lot more effective.
Why not write this as the slide title? Many PowerPoint templates are so poorly designed that people do not use the headline. The headline is set in such a big font that you can only write 3 words. Two thirds of the headline space is taken up by the corporate logo. The elaborate graphic background of the title makes it hard to read what is written there.
In short: clean up the template, start with the headline, and write it where it is supposed to be.