Anticancer T cells acquire a dysfunctional state characterized by poor effector function and expression of inhibitory receptors, such as programmed cell death protein 1 (PD-1). Blockade of PD-1 signalling leads to T cell reinvigoration and is increasingly applied as an effective anticancer treatment. Recent work challenged the commonly held view that the phosphatase Src homology 2 (SH2) domain–containing phosphatase (SHP)-2 is essential for the molecular cascade downstream PD-1, suggesting functional redundancy with the homologous phosphatase SHP-1. Therefore, we investigated the effect of concomitant SHP-1 and 2 deletion in T cells on their ability to mount antitumour immune responses. In vivo data shows that neither sustained or acute SHP-1/2 deletion improves T cell mediated tumour control. The loss of SHP-1/2 also impairs the therapeutic effects of anti-PD1 treatment. In vitro results show that SHP-1/2-deleted CD8+ T cells exhibit impaired expansion due to a survival defect and proteomics analysis reveals substantial alterations in their proteome, including in apoptosis-related pathways. This data indicates that concomitant ablation of SHP-1/2 in polyclonal T cells fails to improve their anticancer properties, implying that caution shall be taken when considering their inhibition for immunotherapeutic approaches.