CD274 and classic Hodgkin lymphoma: In agreement with the evaluation model for immunohistochemical expression of PD-L1 in tumors, we proposed a scoring system for TIGIT immunohistochemistry in CHL; moreover, we compared TIGIT results with PD-1 and PD-L1 expression to obtain a complete assessment of the immunomodulation of Hodgkin lymphoma microenvironment.