ICOS and neoplasm: ICOS/ICOSL has dual roles with both pro- and anti-tumor activities, leading to T cell activation but also Treg differentiation, justifying the development of both anti-ICOS agonists (GSK3359609, JTX-2011) (NCT04428333, NCT02904226) and antagonists (MEDI-570, KY1044/Alomfilimab/SAR445256) (NCT02520791, NCT03829501).