In some embodiments, the invention includes a therapeutic combination of a phosphoinositide 3-kinase (PI3K) inhibitor, including PI3K inhibitors selective for the γ- and δ-isoforms and selective for both γ- and δ-isoforms, and a Bruton's tyrosine kinase (BTK) inhibitor. In some embodiments, the invention includes therapeutic methods of using a BTK inhibitor and a PI3K-δ inhibitor to treat solid tumor cancers by modulation of the tumor microenvironment, including macrophages, monocytes, mast cells, helper T cells, cytotoxic T cells, regulatory T cells, natural killer cells, myeloid-derived suppressor cells, regulatory B cells, neutrophils, dendritic cells, and fibroblasts.
