HAVCR2 and head and neck squamous cell carcinoma: In the immune checkpoint network, TP63+ SLC7A5+ HNSCC subpopulation communicated with TAM subpopulations via the CD24-SIGLEC10 axis, whereas SPP1+ TAM subpopulation interacted with other immune cell subpopulations and CAF subpopulations through the LGALS9-HAVCR2 axis (Figure 8B).