CD274 and neoplasm: In line with these works, we also found PD-L1 immunoexpression to be the highest in CH (which is not surprising, since this tumor subtype resembles placental tissue, which is precisely one of the most universal positive control samples used for PD-L1 testing, related to the need for regulating immune response against the growing fetus—the fetomaternal tolerance [44]) followed by EC and SE, and lowest in YST and TE [15].