sdcc is san diego comic con. It's a big event for fans of all fandoms. It's 4 days every year and takes place in san diego. Other than walking around merchandise, it also has many activities, and you can also attend celebrity panels if you are lucky!
Bro knows nothing about the mcu let me humble him. The world would not have accepted a former brainwashed assassin as captain America as we saw In the falcon to show it was hard for sam to establish himself as captain America we also see this in the brave new world teasers