So now a new multimillion-pound research programme aims to discover why at least half of all patients fail to respond to immunotherapy or suffer from those debilitating side effects.

Now 42, Alex was first diagnosed with melanoma in 2012.

He was operated on but three years down the line, cancer had spread to his lymph nodes.

Alex had a series of surgeries to remove tumours and then a session of radiotherapy after surgery and later immunotherapy.

"I ended radiotherapy but my scans were clear however, less than two years down the line, my cancer came back," he said.

"I was offered immunotherapy and it totally saved my life."

It was life-changing treatment for me, and I am now eight years into being completely in remission and able to lead a normal and active life.

"But without it I would have been expected to have died in 2019 leaving behind my wife and two children aged four and seven at the time."

But Alex, a lawyer from Surrey, is urging caution with the treatment.

"While the results from the treatment have been phenomenal, it did come with its tough lessons," he said.

"I had quite some pretty significant side effects that led to two weeks in the hospital. I have no doubt about the need for research and education about the side effects of immunotherapy to make the treatment as effective and gracious as possible."

It is a research project which brings together 16 academic institutions and NHS trusts and health boards from throughout the UK to work with 12 bioscience and technology companies.

One of the problems to be examined by the scientists is a lack of testable and usable biomarkers, those tiny molecules that can inform doctors whether or not someone is likely to benefit from a given drug.

Identify them, and you could possibly be helping in two ways: both in choosing patients likely to benefit most but also, possibly opening new treatments, including vaccines and cell therapies.

The project will recruit 3,000 patients who have already completed their treatment and then 3,000 more starting the treatment across the UK for breast, bladder, kidney, and skin cancer.

Other types of cancer may be included as the research goes on.

Prof Samra Turajlic has specialized in cancer at the Royal Marsden hospital and will lead the project for the Francis Crick Institute in London.

"Immense progress has been made with immunotherapy in cancer over the past years," Prof Turajlic said.

"We still shortchange many patients because of treatment failure and side effects," she said.

"We have a very unique opportunity in the UK, especially with the NHS to address this challenge.

"We will be one step closer to better tests in the clinic, but also fuel more discoveries about cancer immunology and new therapies.

"In the grand scheme of things, we want to accelerate how we deliver personalised medicine for a disease that affects enormous numbers of people within the UK year after year."