We Are Still In is a left-of-center coalition of state and local governments, businesses, investors, universities, and other organizations created by the left-of-center Bloomberg Philanthropies to create the image of a grassroots initiative in support of the Paris Climate Accords, an environmentalist pseudo-treaty negotiated by the Obama administration, not submitted to the United States Senate for ratification, and repudiated by the Trump administration. 
It is a sister pop up to “America’s Pledge,” another Bloomberg-backed entity supporting the accords. 
Formed in June of 2017 in protest of President Donald Trump’s announcement that he would withdraw the United States from the Paris Climate Accords, We Are Still In is a left-of-center “pop up” created by Bloomberg Philanthropies, the philanthropic arm of billionaire former New York Mayor and unsuccessful 2020 Democratic presidential candidate Michael Bloomberg. Efforts are focused on gaining signatories to a declaration that commits them to carbon-emission-reduction targets set in the Paris Climate Accords and establishes voluntary tracking of progress towards the goals. 
Signatories include businesses, investors, cities, counties, colleges, health care organizations, faith groups, states, and tribes that represent $9.5 trillion of the U.S. economy.  Those supporting We Are Still In’s declaration include the states of California, New York, and Oregon; the University of California System; and major corporations including Nestle, Unilever, Apple Microsoft, and Twitter. 
Coordinating organizations beyond Bloomberg Philanthropies include the World Wildlife Fund, Sierra Club, Climate Mayors, Environmental Entrepreneurs, and the American Sustainable Business Council.  
On November 30, 2019 Speaker of the House of Representatives Nancy Pelosi (D-CA) appeared at the U.N. Climate Change Conference in Madrid and proclaimed that “we’re still in” and gave an exclusive interview to Bloomberg Environment prior to her appearance.  
The We Are Still In campaign is led by former California Governor Jerry Brown (D) and Michael Bloomberg, former Mayor of New York City, unsuccessful Democratic presidential candidate, founder of Bloomberg LP and benefactor of Bloomberg Philanthropies. 
We Are Still In backed by a $70 million commitment from Bloomberg Philanthropies for it and America’s Pledge. another left-of-center pop up created by Michael Bloomberg to advance environmentalist activism.