C4A and cancer: To better understand the relationship between the intersection of HCC immunotypes and six pan-cancer immunotypes, we extracted molecular subtype data from a previous study [38] and determined that the IS1 subtype was composed mainly of the C2 and C3 subtypes, the IS2 subtype was composed mainly of the C4 subtype, and the IS3 and IS4 subtypes were composed mainly of the C3 and C4 subtypes (Fig. 4c).