Upfronts season is just two months away and while a handful of major networks including Fox News and A+E Networks have muddied the waters by cancelling upcoming showcases, AT&T is showing no signs of slowing down. Something AT&T has been working on for a while now is pushing Xandr, the operator’s advertising technology arm, closer towards WarnerMedia – in an effort to harmonize operations and grow the technology’s powerful audience targeting potential to ultimately increase the value of ad slots. AT&T is thinking big; bigger than getting it ready for the world’s most lucrative annual entertainment sales gathering. This week, AT&T finally revealed a few collaborative fruits from Xandr and WarnerMedia – which it transpires had third-party involvement from Disney…