MKI67 and neoplasm: In B16 tumours, the Toxlo population consisted of five main subclusters, including two Mki67+ proliferating Teff cell populations (Prolif1 and Prolif2), two progenitor Tex cell populations (TexProg1, TexProg2), an intermediate exhausted (TexInt) population and a small naive-like cell population (Fig. 3a and Extended Data Fig. 6a,b).