M phase or Mitosis involves the process of cell duplication in which one parental cell divides into two genetically identical daughter cells.
Mitosis is a process of the M phase that includes stages like prophase, metaphase, anaphase, and telophase.
The last stage of mitosis is the telophase in which the newly produced chromosomes reach the poles and form the nuclear membrane and begin to decondense into their interphase conformations.
Cytokinesis is the process that runs during telophase and it leads to the splitting of the cytoplasm into two daughter cells.
Hence, The M phase usually ends with the division of cytoplasm (cytokinesis).