Cartesian and co-Cartesian morphisms. Maybe other fibrations in used for adjunctions.
Definition of Adjunction via correspondences (See sect 5.2.1 and 5.2.2 in HTT)
Statement of Prop 5.2.1.3 (HTT) (probably skip the proof)
Prop. 5.2.3.5, sketch of proof.
Links:
[1] http://www.mpim-bonn.mpg.de/taxonomy/term/39
[2] http://www.mpim-bonn.mpg.de/node/4234
[3] http://www.mpim-bonn.mpg.de/node/4676