For some cancers ( notably bladder ) the probability of benefit is related to PD - L1 expression .
Most cancers with PD - L1 expression still do not respond , and many ( about 15 % ) without PD - L1 expression do respond .
For some cancers ( notably bladder ) the probability of benefit is related to PD - L1 expression , but most cancers with PD - L1 expression still do not respond , and many ( about 15 % ) without PD - L1 expression do respond .