Moderna  (MRNA)  shares surged higher Wednesday after the drugmaker said it will work with Merck & Co  (MRK)  to develop and market an mRNA structed cancer vaccine.

With the size of the COVID-19 vaccine market expected to contract in subsequent years from the levels seen in 2021, Moderna has been pinning its hopes on its non-COVID vaccines which includes influenza and respiratory syncytial virus shots.

The cancer vaccine is tailored for each patient to generate T-cells, a key part of the body's immune response, based on the specific mutational signature of a tumor.

In 2016, Merck and Moderna entered a strategic partnership to develop a personalized vaccine for treatment of various types of cancer.

Merck and Moderna have collaborated on personalized cancer vaccines since 2016, Moderna President Stephen Hoge said in a written statement.

Merck in 2020 sold its equity investment in Moderna, benefiting from a surge in the vaccine-maker's stock price that year.

Moderna said it will seek unspecified relief in both a U.S. and German court after altering its pledge not to enforce patents related to its mRNA-1273 coronavirus vaccine, known as Spikevax in wealthy countries.

But MRNA stock has trended lower since February 2021, leaving investors to ask what's next. The question is even more important as demand for Covid vaccines drops off.