"Red-Green alliance" - red for the left/socialists, green for Islamists. It is not a formal organization, it is used to describe temporary coalitions where groups with very different end-goals share a common opponent - usually described as anti-imperialism, anti-capitalism, anti-Americanism, or anti-Zionism.
Example: Encampments at Columbia, UCLA, Michigan etc. were jointly organized by Students for Justice in Palestine (SJP), Democratic Socialists of America (DSA) chapters, and local chapters of Islamist advocacy groups. Demands combined left language (divestment, decolonization, anti-capitalism) and Islamist language (From the River to the Sea, resistance as religious duty).