FOXP3 and spinal chordoma: Multiplexed quantitative immunofluorescence staining was used to determine the TIL levels in the tumoral and stromal subareas of 114 spinal chordoma specimens (54 in the training and 60 in the validation cohort) for programmed death‐1 (PD‐1), CD3, CD8, CD20 (where CD is cluster of differentiation), and FOXP3.