I love to find videos or apps that help review or overview essential concepts. I'll have to work on finding & sharing the ones I've found so far, but this one was even better than the one from Pfizer. This is slightly longer, just under 7 minutes, but it's a more complete overview of the immune system. It still isn't perfect, but it's hard to get a good, complete, perfectly accurate overview of an entire system in such a short video. This is one of the best I've seen. I haven't watch the other videos, but I'll be checking them out - watch for updates on the channel here. Why You Are Still Alive - The Immune System Explained
Another video from LinkedIn, this video from Pfizer shares how the immune system creates an inflammatory response and how the response works against the body in auto-immune disorders. The video is less than 5 minutes, and is only the most cursory of discussions, but it's a decent start and might be a semi-decent way to review these concepts if you need it.