Here Paul speaks of both the "flesh" and the "spirit" as if they were living persons. AT: "the way sinful people think ... the way people who listen to the Holy Spirit think" (See: [[rc://en/ta/man/translate/figs-personification]])
# death
Here this means the separation of a person from God.
# Those who are in the flesh
This refers to people who do what their sinful nature tells them to do.