Police officers called to the scene on Westgate Street, E8, administered the woman CPR.
They were contacted at 8.52pm but a crime scene is still in place as officers investigate.
Footage of the scene published on social media showed several police units within the cordoned area, as well as at least one ambulance.
No arrests have been conducting at the time of writing.
Express.co.uk has approached Hackney Police for comment.
The victim who is believed to be in her 30s was found with a gunshot injury, according to a Met Police report.
She was taken to an east London hospital and her next of kin were contacted.
The Met Police have launched an appeal for eye-witnesses or anyone with information that could help with the inquiry.
In a separate incident in South London, a man in his 20s was stabbed to death, according to reports.
The incident took place in Ramilles Close, SW2, in the Brixton Hill area of the capital.
“No arrests have been made at this stage.
“A crime scene remains in place at the location, and officers are continuing their enquires.”
The Mayor’s Office for Policing And Crime (Mopac) is working to tackle the know crime crisis in the capital.
It released a statement outlining the Mayor’s strategy for “making London safer for young people”.
The statement read: “Every time a young Londoner dies as a result of violent crime it is absolutely heart-breaking and leaves families and communities devastated.
“The causes of violent crime are extremely complex and involve deep-seated problems, like inequality, poverty, social alienation and a lack of opportunities for young people.
“These issues have been made far worse by the Government’s cuts over the past decade to the police and preventative services, like youth centres, council services and charities, as well as the growing illegal drugs market.”