Meaning
Two thick parallel bars, a bold equals sign that arrived with emoji version 14.0. It means equal to, results in, or the same as.
It completes emoji maths jokes and little formulas for life: “Coffee ➕ sunshine 🟰 good mood” People also use it to say two things are basically the same or that one leads to another. Before it existed, people typed a normal equals sign, which still works anywhere.