The novel cobalt-nickel-based superalloys have been introduced and developed based on the strengthening effect of the γ′ order compound in nickel-based superalloys. The aim of the present study is to investigate the effects of temperature and strain rate during compression testing on the microstructural evolution of a Co-22.8Ni-3.4Al-8Cr-17.1W-1.5Ti-2.8Ta-1.5Nb-1.5Mo-0.06C-0.02B (wt.%) superalloy. In this study, hot compression tests were performed within a temperature range of 1050–1200°C, with 50°C intervals, and at strain rates of 0.1 s⁻¹ and 0.001 s⁻¹, up to a strain of 0.7. Microstructural evolution was analyzed using Optical Microscopy, Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) analysis. The results showed that as the temperature increased from 1050 to 1200°C and the strain rate decreased from 0.1 s⁻¹ to 0.001 s⁻¹, the flow stress decreased. Microstructural studies indicated that at a strain rate of 0.1 s⁻¹, increasing the temperature from 1050 to 1100°C did not lead to the onset of recrystallization; elongated grains were still present in the structure. At 1150°C, dynamically recrystallized grains began to nucleate and grow around the initial and pre-existing grain boundaries. Dynamically recrystallized grains were also observed on precipitates, indicating that the recrystallization mechanism was particle-stimulated nucleation. At 1200°C, the development of dynamic recrystallization was observed in certain regions of the structure. At a strain rate of 0.001 s⁻¹ from 1050°C, the development of dynamic recrystallization was observed throughout the structure. At 1150°C and a strain rate of 0.001 s⁻¹, the structure was fully recrystallized, displaying equiaxed grains with a uniform size distribution.