This clinical trial evaluates whether an online cognitive training intervention (Intervention to enhance Cognitive Augmentation and Neuroplasticity \[I-CAN\]), delivered before and after treatment with chimeric antigen receptor T-cell therapy, works to improve cognitive and neurological outcomes in patients with multiple myeloma or B-cell non-Hodgkin lymphoma that has come back after a period of improvement (relapsed) or does not respond to treatment (refractory). Cancer treatment can have significant short and long-term side effects, including cognitive and neurological side effects such as impairments in attention, memory, language, and executive function. The I-CAN program is a form of cognitive training. Cognitive training is a therapeutic approach designed to improve and restore cognitive functioning, based on the brain's ability to reorganize and form new neural connections to accomplish tasks. I-CAN provides five core elements necessary for training the brain to create new neural connections including speed of processing, accuracy of processing, adaptivity, generalizability, and engagement. The I-CAN intervention, when delivered before and after therapy, may help reduce the cognitive side effects of treatment in patients with relapsed or refractory multiple myeloma or B-cell non-Hodgkin lymphoma.