In which TV series is Seong Gi-hun a main character?

Who played Ted Lasso in 'Ted Lasso'? Who played Roy Kent in 'Ted Lasso'? Who played Beth Harmon in 'The Queen's Gambit'? Who played Seong Gi-hun in 'Squid Game'? Who played Charles-Haden Savage in 'Only Murders in the Building'? In which TV series is Charles-Haden Savage a main character? Who played Oliver Putnam in 'Only Murders in the Building'? Who played Mabel Mora in 'Only Murders in the Building'?