Using Outlook for Android for personal email and calendar management
That certainly sounds like a phishing attempt.
As the AI says, you should check the mail address in the From line. Often with spams, the address is somewhere far out. Sometimes they are a little more deceivable like hotmail-microsoft.com. (That is just something I made up, and I would not expect it to be a legit address.)
Also hover over any links and see where they go. (You should be able to see that in the status bar.) They should end in hotmail.com, nothing else. Do not click any links until you have verified that the link is legit.
Also, what does the text say? That you have to confirm that you want to keep the email? In such case, I am very sure it is phishing. I don't use Hotmail, but typically the response to a delete request would be that you have to confirm the deletion (in case some joker fake a request on your behalf).