Abstract: The present disclosure provides methods of treating B-cell malignancy in a subject with a Bcl-2 inhibitor, in particularly 2-((1H-pyrrolo[2,3-b]pyridin-5-yl)oxy)-N-((4-((((1r,4r)-4-hydroxy-4-methylcyclohexyl)methyl)amino)-3-nitrophenyl)sulfonyl)-4-(2-((S)-2-(2-isopropylphenyl)pyrrolidin-1-yl)-7-azaspiro[3.5]nonan-7-yl)benzamide or a pharmaceutically acceptable salt thereof, or its combination with a Bruton's tyrosine kinase (BTK) inhibitor, particularly (S)-7-(1-acryloylpiperidin-4-yl)-2-(4-phenoxyphenyl)-4,5,6,7-tetrahydropyrazolo-[1,5-a]pyrimidine-3-carboxamide or a pharmaceutically acceptable salt thereof.