CD274 and lymphopenia: The most frequent Grade ≥3 hematological laboratory abnormalities were lymphopenia in all cohorts (27.8% [cHL anti‐PD‐1/PD‐L1 naïve], 8.3% [cHL anti‐PD‐1/PD‐L1 progressors], 43.8% [DLBCL], and 36.4% [PTCL]), and thrombocytopenia (36.4%) in the PTCL cohort (Table 3).