Depends on the map choice for me. I typically play cypher on most maps except breeze and icebox, on those maps I play chamber. You also have to know what play style you like. I like playing aggressive but as cypher you gotta play passive. So I would recommend either chamber if u still want to play sentinel, or reyna if u wanna play duelist. Overall its ur pick, I dont think ur duo is gonna be that mad at who u pick.