This is a symbol of Captain America, one of the superheroes of Marvel Comics. Captain America always wears a suit that has this logo of six identical stripes with a star in between that people have started to associate this image with him, so that whenever they see this sign they immediately think of Captain America. Also the artist could have simply drawn Captain America but instead he smartly chose to use this sign to signify him rather than draw a real picture instead.
Spiderman from Captain America: Civil War, played by Tom Holland. He did a really good job, making the character humorous, noble, and endearing as ever. Also, Holland is an experienced gymnast, so he could do the required stunts. Cool? I think so.