Short answers, pulled from the story.
Inanna was the ancient Mesopotamian goddess of war, love, and sex, also associated with political power, divine law, sensuality, and procreation. Originally worshipped in Sumer, she was known to the Akkadians, Babylonians, and Assyrians as Ishtar. Her primary title was "the Queen of Heaven" and she was the patron goddess of the Eanna temple at Uruk.
In the myth, Inanna descends through seven gates to the underworld ruled by her sister Ereshkigal, surrendering a piece of clothing or jewelry at each gate. Stripped of all power, she is judged by the seven judges of the underworld and killed. After three days, Enki creates two sexless beings who revive her with the food and water of life. She returns to the living world, but her husband Dumuzid is taken to the underworld as her replacement.
Inanna was worshipped in Sumer as early as the Uruk period, roughly 4000 to 3100 BCE. Her worship continued through the Akkadian, Babylonian, and Assyrian periods. The cult declined gradually between the first and sixth centuries CE in the wake of Christianity.
Inanna was identified with the planet Venus, and in archaic Uruk she was worshipped as morning Inanna and evening Inanna, tracking the two phases of Venus in the sky. A cylinder seal from the Jemdet Nasr period indicates that ancient Sumerians knew the morning and evening stars were the same celestial object. Theology professor Jeffrey Cooley has argued that Inanna's movements in many myths correspond with the movements of Venus across the sky.
Scholars believe Inanna and Ishtar were originally separate, unrelated deities who became conflated during the reign of Sargon of Akkad, in the Akkadian period from roughly 2334 to 2154 BCE. Sargon's daughter Enheduanna, an Akkadian poet, wrote numerous hymns to Inanna explicitly identifying her with Ishtar, which caused the popularity of the combined cult to increase dramatically.
Individuals who practiced gender nonconformity were heavily involved in Inanna's cult. During Sumerian times, priests known as gala worked in Inanna's temples, performing elegies; men who became gala sometimes adopted female names. During the Akkadian period, kurgarru and assinnu were servants of Ishtar who dressed in female clothing and performed war dances in her temples. One Akkadian hymn describes Ishtar as transforming men into women, and women into men.