CD274 and neoplasm: When the tumor microenvironment is subtyped into four types according to the presence or absence of PD-L1 expression and the presence or absence of TILs, TIL-positive/PD-L1 positive Type I and TIL-positive/PD-L1 negative Type IV are considered as “Hot tumors” in which anti-PD-1 antibodies are effective alone or in combination [36].