From an article focusing on Marvel's Yelenova Belova character:
Another way Marvel shrinks payments is by classifying some film appearances as “cameos.” According to sources, if a character appears for less than 15 percent of screen time, that’s considered a cameo — and thus its creators are due less money. By that standard, Sebastian Stan’s Winter Soldier, a character key to Captain America: Civil War, would be considered a cameo; he appeared in 22 minutes (just under 15 percent) of its 2 hour, 28 minute run time. Ditto for Captain America, who appeared for less than 7 minutes, 30 seconds of Avengers: Infinity War.
One potential money saver for Marvel is the world of video games, which every year eclipses the box office in terms of entertainment market share. According to sources, Marvel will pay creators for character appearances on console games only — not mobile games, a segment gaming observers note is on a fast rise and one source likens to being offered VHS royalties in an era in which Blu-ray is about to be the dominant force.