Article History
First Online: 14 August 2018
Compliance with Ethical Standards
:
: No funding was used in the preparation of this review article.
: RC has received honoraria for consultancy and advisory boards from BMS, MSD, Roche, AstraZeneca/Medimmune, Takeda and Novartis; RC declares not owning any stock in any of these companies. FG, RT and JC declare that they have no conflicts of interest that might be relevant to the contents of this review.