To determine the differences between primary and recurrent lesions, we calculated the proportion of cells in each cluster among all cells in primary and recurrent lesions and found that the proportions of CD4 T cells, CD8_GZMK T cells and CD8_ZNF683 T cells in recurrent chordomas were lower than those in primary lesions (Figure S5), indicating that there might be a more immunosuppressive state in recurrent lesions. Here, CD4 is linked to chordoma.