A report by the National Academies of Science says the way NASA is trying to find life on the solar system is misguided. The panel says NASA focuses to much on the type of life that can be found on Earth.
The report lays out a straightforward list of basic requirements for something that we might recognize as life:
A thermodynamic disequilibrium of some sort, from which energy can be harvested.
A chemical environment that allows the persistence of covalent bonds.
A liquid environment.
A molecular inheritance system that can support Darwinian evolution.
With those conditions in mind, the report discusses how many of those requirements can be met by things other than the water, nucleic acids, etc., that characterize known life. Given this discussion, it considers NASA's efforts to find life elsewhere in the solar system as misguided, given that they have been focused on identifying signs of the chemicals that typify life on Earth.
The authors note that most locales in the solar system appear to be at a thermodynamic disequilibrium, and many of those have solvents present in liquid form. Those liquids can support a mix of conditions, some of which could support relatively Earth-like life and others that might support "weird" life; the report considers these two separately.