PDCD1 and neoplasm: In experiments conducted in mouse models by Seifert et al, it has been shown that there is increased proliferation of intratumoral CD8+ T cells while inducing apoptosis of regulatory T cells, when a combination therapy of Imatinib and PD-1/PD-L1 blockade was used.[10] This in vivo model suggests that the combination therapy could have a role in altering the tumor microenvironment by changing the tumor from cold to hot, and ultimately making it more responsive to immunotherapy.