Using Xfinity APP on iphone to stream to non-WIFI TV

I DO NOT have internet access via WIFI. I MUST use my iphone. I use the Xfinity streaming app to watch TV channels on the go, but the screen is so small. I would love to connect my iphone to my TV--non-WIFI capable--via a lightning to HDMI convert cable. So why does the Xfinity content not display on my TV???  I can see my iphonde screen when I connect the iphone to my TV via the cable.  I can watch FOXNEWS and other content, but not Xfinity.