CD4 and osteosarcoma: A study unveiled differential CD8 Tex cells within the osteosarcoma microenvironment which found that patients in the low CD8 Tex score group demonstrated a more favorable prognosis, increased immune cell infiltration, and heightened responsiveness to treatment compared to those in the high CD8 Tex score group.[51] The promoting infiltration of CD4 Treg cells predicts poor prognosis in osteosarcoma patients.[52] This suggests that HTR2B activation could modulate the immune landscape to enhance antitumor responses.