All Incoming mail goes straight to my Junk folder not my inbox. This is true for mail on my MacBook Pro, iPhone and iPad. I'm using Mail 12.4 with Mojave 10.14.6. I cannon find any preferences or filters, etc to correct. This started 4 days ago. Help

No banner, Messages just go into junk folder. Comcast says they think the problem is somehow in the filtering of the Apple Mail App

If there is no banner, it is either Comcast putting the messages in the Spam folder, or if some email server marked the messages with spam headers, Mail's junk filter defaults to trusting those headers. You can disable that in Mail's Preferences > Junk.

If Mail moves the messages, it marks them as Junk. Just to clarify, it is not a notification. The banner is at the top of the message when you view it.

On the Mac, do they have the yellow banner that says that Mail thinks they are Junk?

If not, it may be your email provider moving them all to the spam folder.