what is the mexican soccer player wearing on his head

He’s wearing a protective headband/headguard. It’s associated with Raúl Jiménez, the Mexico striker, and he wears it because of a serious skull injury he suffered in 2020.

Why he wears it

• It helps protect the area of the earlier injury during matches.

• Reports say he’s been told to keep wearing it for the rest of his career.

What it looks like

• It’s a custom, medically approved piece of headgear, often described as black.

• Some coverage calls it a headband, while others call it a headguard or protective headgear.

If you mean a different Mexican player, the name would help narrow it down.