It’s probably more about the self shading and reflection that isnt created by an HDRI but surrounding objects (eg. the main differences of game engines and pathtracers). He’s probably faking some of it with colorbleeds and screenspace magics like SSAO.

The thing is... Deadpool is exactly as people expected the character from the comics (which obviously works because the comics thrive on him and he would work in any setting). Most superhero movie adaptations disappoint in one way or another when compared to their comic book counterparts.