PDCD1 and cancer: Provided that both the immune system and chemotherapy kill tumor cells by inducing apoptosis [38] and given the high prevalence and impact that alterations in cytoplasmic kinases have in human cancer in general and in apoptosis resistance in particular, alterations affecting these kinases may also cause the lack or partial response to PD-1/PD-L1 blockade and would also support previous kinase profiling studies and patient’s active monitoring [95] as valuable tools to enhance patient response to such treatments.