At first glance you might think that there is no reaction, that the "products" would be CuI2 and K2SO4, and that both are soluble in water since CuCl2, another copper(II) halide is soluble in water.
But instead, there is an interesting redox reaction which occurs. The iodide ion will reduce the copper(II) ion to copper(I) while iodide itself is oxidized to elemental iodine. Like most copper(I) compounds, CuI is insoluble in water.