The phrase "advanced talks" means that people or groups are having serious and detailed discussions about something, and they are closer to reaching an agreement or making a decision. Full definition
The online home rental startup is reportedly in advanced talks to raise funding that would make it more valuable than some large hotel operators. (entrepreneur.com)
The companies were in advanced talks, according to one source. (fortune.com)
David Alaba is in advance talks with Arsenal according to some sources. (justarsenal.com)